Absolutely not. There is no water-based liquid which can decompose diamonds at room temperature. Maybe no room-temperature liquid of any kind. The bonds between carbons atoms in diamonds need a lot of energy to break, before otherwise natural reactions of carbon can occur. If you put stomach acid in a stainless steel pressure tank and heated it to 200-300C, you might dissolve a little of your diamond. Concentrated Phosphoric Acid dissolves glass and many rocks at 200C, and may have some effect on diamond. Pure, elemental brown liquid Bromine (Br2) comes close, but probably does not do it at room temperature. Even chlorine gas liquefied by pressure might not. Fluorine gas pressurized to 10 atmospheres could burn it with an intense white flame, but until the flame was ignited, the diamond would not dissolve. Whether a reaction occurs or stalls might actually depend on subtleties like the color of the diamond, or more precisely, its impurities and electrical carrier type. Yellowish Nitrogen-doped N-type diamonds might require a slightly higher temperature to start to dissolve than boron-doped P-type diamonds, when one is using an oxidizing chemical to dissolve it. Oxygen and Fluorine are oxidizers, liquid sodium is a reducer, and the HCL in stomach acid would be attempting a mixed reduction-oxidation reaction, which works well enough on some crystals. Molten Sodium Hydroxide + Sodium Nitrate at 400 degrees C might do a fair job of slowly dissolving diamonds completely. When done, you would have some sodium carbonate in the melt. Lots of molten metals do it, but they are all hotter than that. Molten iron is fast, but it is 1500C. I have had no real experience dissolving diamonds. The temperature thresholds described might be lower or higher than the reality. But it gives you the appropriate perspective that etching at room temperature is not likely for diamonds. About the only gem that stomach acid could etch would be a pearl. And it is a product of biology, not geology.
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Synthetic diamonds of various colors grown by the high-pressure high-temperature technique
A synthetic diamond (also known as an artificial diamond, cultured diamond, or cultivated diamond) is diamond produced in an artificial process, as opposed to natural diamonds, which are created by geological processes. Synthetic diamond is also widely known as HPHT diamond or CVD diamond after the two common production methods (referring to the high-pressure high-temperature and chemical vapor deposition crystal formation methods, respectively). While the term synthetic is associated by consumers with imitation products, artificial diamonds are made of the same material (pure carbon, crystallized in isotropic 3D form). In the U.S., the Federal Trade Commission has indicated that the alternative terms laboratory-grown, laboratory-created, and -created “would more clearly communicate the nature of the stone”.
Numerous claims of diamond synthesis were documented between 1879 and 1928; most of those attempts were carefully analyzed but none were confirmed. In the 1940s, systematic research began in the United States, Sweden and the Soviet Union to grow diamonds using CVD and HPHT processes. The first reproducible synthesis was reported around 1953. Those two processes still dominate the production of synthetic diamond. A third method, known as detonation synthesis, entered the diamond market in the late 1990s. In this process, nanometer-sized diamond grains are created in a detonation of carbon-containing explosives. A fourth method, treating graphite with high-power ultrasound, has been demonstrated in the laboratory, but currently has no commercial application.
The properties of synthetic diamond depend on the details of the manufacturing processes; however, some synthetic diamonds (whether formed by HPHT or CVD) have properties such as hardness, thermal conductivity and electron mobility that are superior to those of most naturally formed diamonds. Synthetic diamond is widely used in abrasives, in cutting and polishing tools and in heat sinks. Electronic applications of synthetic diamond are being developed, including high-power switches at power stations, high-frequency field-effect transistors and light-emitting diodes. Synthetic diamond detectors of ultraviolet (UV) light or high-energy particles are used at high-energy research facilities and are available commercially. Because of its unique combination of thermal and chemical stability, low thermal expansion and high optical transparency in a wide spectral range, synthetic diamond is becoming the most popular material for optical windows in high-power CO2 lasers and gyrotrons. It is estimated that 98% of industrial grade diamond demand is supplied with synthetic diamonds.
Both CVD and HPHT diamonds can be cut into gems and various colors can be produced: clear white, yellow, brown, blue, green and orange. The appearance of synthetic gems on the market created major concerns in the diamond trading business, as a result of which special spectroscopic devices and techniques have been developed to distinguish synthetic and natural diamonds.
Moissan trying to create synthetic diamonds using an electric arc furnace
After the 1797 discovery that diamond was pure carbon, many attempts were made to convert various cheap forms of carbon into diamond. The earliest successes were reported by James Ballantyne Hannay in 1879 and by Ferdinand Frédéric Henri Moissan in 1893. Their method involved heating charcoal at up to 3500 °C with iron inside a carbon crucible in a furnace. Whereas Hannay used a flame-heated tube, Moissan applied his newly developed electric arc furnace, in which an electric arc was struck between carbon rods inside blocks of lime. The molten iron was then rapidly cooled by immersion in water. The contraction generated by the cooling supposedly produced the high pressure required to transform graphite into diamond. Moissan published his work in a series of articles in the 1890s.
Many other scientists tried to replicate his experiments. Sir William Crookes claimed success in 1909. Otto Ruff claimed in 1917 to have produced diamonds up to 7 mm in diameter, but later retracted his statement. In 1926, Dr. J Willard Hershey of McPherson College replicated Moissan’s and Ruff’s experiments, producing a synthetic diamond; that specimen is on display at the McPherson Museum in Kansas. Despite the claims of Moissan, Ruff, and Hershey, other experimenters were unable to reproduce their synthesis.
The most definitive replication attempts were performed by Sir Charles Algernon Parsons. A prominent scientist and engineer known for his invention of the steam turbine, he spent about 40 years (1882–1922) and a considerable part of his fortune trying to reproduce the experiments of Moissan and Hannay, but also adapted processes of his own. Parsons was known for his painstakingly accurate approach and methodical record keeping; all his resulting samples were preserved for further analysis by an independent party. He wrote a number of articles—some of the earliest on HPHT diamond—in which he claimed to have produced small diamonds. However, in 1928, he authorized Dr. C.H. Desch to publish an article in which he stated his belief that no synthetic diamonds (including those of Moissan and others) had been produced up to that date. He suggested that most diamonds that had been produced up to that point were likely synthetic spinel.
GE diamond project
A belt press produced in the 1980s by
In 1941, an agreement was made between the General Electric (GE), Norton and Carborundum companies to further develop diamond synthesis. They were able to heat carbon to about 3,000 °C (5,430 °F) under a pressure of 3.5 gigapascals (510,000 psi) for a few seconds. Soon thereafter, the Second World War interrupted the project. It was resumed in 1951 at the Schenectady Laboratories of GE, and a high-pressure diamond group was formed with Francis P. Bundy and H.M. Strong. Tracy Hall and others joined this project shortly thereafter.
The Schenectady group improved on the anvils designed by Percy Bridgman, who received a Nobel Prize for his work in 1946. Bundy and Strong made the first improvements, then more were made by Hall. The GE team used tungsten carbide anvils within a hydraulic press to squeeze the carbonaceous sample held in a catlinite container, the finished grit being squeezed out of the container into a gasket. The team recorded diamond synthesis on one occasion, but the experiment could not be reproduced because of uncertain synthesis conditions, and the diamond was later shown to have been a natural diamond used as a seed.
Hall achieved the first commercially successful synthesis of diamond on December 16, 1954, and this was announced on February 15, 1955. His breakthrough was using a “belt” press, which was capable of producing pressures above 10 GPa (1,500,000 psi) and temperatures above 2,000 °C (3,630 °F). The press used a pyrophyllite container in which graphite was dissolved within molten nickel, cobalt or iron. Those metals acted as a “solvent-catalyst”, which both dissolved carbon and accelerated its conversion into diamond. The largest diamond he produced was 0.15 mm (0.0059 in) across; it was too small and visually imperfect for jewelry, but usable in industrial abrasives. Hall’s co-workers were able to replicate his work, and the discovery was published in the major journal Nature. He was the first person to grow a synthetic diamond with a reproducible, verifiable and well-documented process. He left GE in 1955, and three years later developed a new apparatus for the synthesis of diamond—a tetrahedral press with four anvils—to avoid violating a U.S. Department of Commerce secrecy order on the GE patent applications. Hall received the American Chemical Society Award for Creative Invention for his work in diamond synthesis.
An independent diamond synthesis was achieved on February 16, 1953 in Stockholm by ASEA (Allmänna Svenska Elektriska Aktiebolaget), one of Sweden’s major electrical manufacturing companies. Starting in 1949, ASEA employed a team of five scientists and engineers as part of a top-secret diamond-making project code-named QUINTUS. The team used a bulky split-sphere apparatus designed by Baltzar von Platen and Anders Kämpe. Pressure was maintained within the device at an estimated 8.4 GPa for an hour. A few small diamonds were produced, but not of gem quality or size. The work was not reported until the 1980s. During the 1980s, a new competitor emerged in Korea, a company named Iljin Diamond; it was followed by hundreds of Chinese enterprises. Iljin Diamond allegedly accomplished diamond synthesis in 1988 by misappropriating trade secrets from GE via a Korean former GE employee.
A scalpel with single-crystal synthetic diamond blade
Synthetic gem-quality diamond crystals were first produced in 1970 by GE, then reported in 1971. The first successes used a pyrophyllite tube seeded at each end with thin pieces of diamond. The graphite feed material was placed in the center and the metal solvent (nickel) between the graphite and the seeds. The container was heated and the pressure was raised to about 5.5 GPa. The crystals grow as they flow from the center to the ends of the tube, and extending the length of the process produces larger crystals. Initially, a week-long growth process produced gem-quality stones of around 5 mm (1 carat or 0.2 g), and the process conditions had to be as stable as possible. The graphite feed was soon replaced by diamond grit because that allowed much better control of the shape of the final crystal.
The first gem-quality stones were always yellow to brown in color because of contamination with nitrogen. Inclusions were common, especially “plate-like” ones from the nickel. Removing all nitrogen from the process by adding aluminium or titanium produced colorless “white” stones, and removing the nitrogen and adding boron produced blue ones. Removing nitrogen also slowed the growth process and reduced the crystalline quality, so the process was normally run with nitrogen present.
Although the GE stones and natural diamonds were chemically identical, their physical properties were not the same. The colorless stones produced strong fluorescence and phosphorescence under short-wavelength ultraviolet light, but were inert under long-wave UV. Among natural diamonds, only the rarer blue gems exhibit these properties. Unlike natural diamonds, all the GE stones showed strong yellow fluorescence under X-rays. The De Beers Diamond Research Laboratory has grown stones of up to 25 carats (5.0 g) for research purposes. Stable HPHT conditions were kept for six weeks to grow high-quality diamonds of this size. For economic reasons, the growth of most synthetic diamonds is terminated when they reach a mass of 1 carat (200 mg) to 1.5 carats (300 mg).
In the 1950s, research started in the Soviet Union and the US on the growth of diamond by pyrolysis of hydrocarbon gases at the relatively low temperature of 800 °C. This low-pressure process is known as chemical vapor deposition (CVD). William G. Eversole reportedly achieved vapor deposition of diamond over diamond substrate in 1953, but it was not reported until 1962. Diamond film deposition was independently reproduced by Angus and coworkers in 1968 and by Deryagin and Fedoseev in 1970. Whereas Eversole and Angus used large, expensive, single-crystal diamonds as substrates, Deryagin and Fedoseev succeeded in making diamond films on non-diamond materials (silicon and metals), which led to massive research on inexpensive diamond coatings in the 1980s.
In recent years, there has been a rise in cases of undisclosed synthetic diamond melee being found in set jewelry and within diamond parcels sold in the trade. Due to the relatively inexpensive cost of diamond melee, as well as relative lack of universal knowledge for identifying large quantities of melee efficiently, not all dealers have made an effort to test diamond melee to correctly identify whether it is of natural or man-made origin. However, international laboratories are now beginning to tackle the issue head-on, with significant improvements in synthetic melee identification being made.
There are several methods used to produce synthetic diamond. The original method uses high pressure and high temperature (HPHT) and is still widely used because of its relatively low cost. The process involves large presses that can weigh hundreds of tons to produce a pressure of 5 GPa at 1500 °C. The second method, using chemical vapor deposition (CVD), creates a carbon plasma over a substrate onto which the carbon atoms deposit to form diamond. Other methods include explosive formation (forming detonation nanodiamonds) and sonication of graphite solutions.
High pressure, high temperature
Schematic of a belt press
In the HPHT method, there are three main press designs used to supply the pressure and temperature necessary to produce synthetic diamond: the belt press, the cubic press and the split-sphere (BARS) press. Diamond seeds are placed at the bottom of the press. The internal part of press is heated above 1400 °C and melts the solvent metal. The molten metal dissolves the high purity carbon source, which is then transported to the small diamond seeds and precipitates, forming a large synthetic diamond.
The original GE invention by Tracy Hall uses the belt press wherein the upper and lower anvils supply the pressure load to a cylindrical inner cell. This internal pressure is confined radially by a belt of pre-stressed steel bands. The anvils also serve as electrodes providing electric current to the compressed cell. A variation of the belt press uses hydraulic pressure, rather than steel belts, to confine the internal pressure. Belt presses are still used today, but they are built on a much larger scale than those of the original design.
The second type of press design is the cubic press. A cubic press has six anvils which provide pressure simultaneously onto all faces of a cube-shaped volume. The first multi-anvil press design was a tetrahedral press, using four anvils to converge upon a tetrahedron-shaped volume. The cubic press was created shortly thereafter to increase the volume to which pressure could be applied. A cubic press is typically smaller than a belt press and can more rapidly achieve the pressure and temperature necessary to create synthetic diamond. However, cubic presses cannot be easily scaled up to larger volumes: the pressurized volume can be increased by using larger anvils, but this also increases the amount of force needed on the anvils to achieve the same pressure. An alternative is to decrease the surface area to volume ratio of the pressurized volume, by using more anvils to converge upon a higher-order platonic solid, such as a dodecahedron. However, such a press would be complex and difficult to manufacture.
Schematic of a BARS system
The BARS apparatus is the most compact, efficient, and economical of all the diamond-producing presses. In the center of a BARS device, there is a ceramic cylindrical “synthesis capsule” of about 2 cm3 in size. The cell is placed into a cube of pressure-transmitting material, such as pyrophyllite ceramics, which is pressed by inner anvils made from cemented carbide (e.g., tungsten carbide or VK10 hard alloy). The outer octahedral cavity is pressed by 8 steel outer anvils. After mounting, the whole assembly is locked in a disc-type barrel with a diameter about 1 meter. The barrel is filled with oil, which pressurizes upon heating, and the oil pressure is transferred to the central cell. The synthesis capsule is heated up by a coaxial graphite heater and the temperature is measured with a thermocouple.
Chemical vapor deposition
Free-standing single-crystal CVD diamond disc
Chemical vapor deposition is a method by which diamond can be grown from a hydrocarbon gas mixture. Since the early 1980s, this method has been the subject of intensive worldwide research. Whereas the mass-production of high-quality diamond crystals make the HPHT process the more suitable choice for industrial applications, the flexibility and simplicity of CVD setups explain the popularity of CVD growth in laboratory research. The advantages of CVD diamond growth include the ability to grow diamond over large areas and on various substrates, and the fine control over the chemical impurities and thus properties of the diamond produced. Unlike HPHT, CVD process does not require high pressures, as the growth typically occurs at pressures under 27 kPa.
The CVD growth involves substrate preparation, feeding varying amounts of gases into a chamber and energizing them. The substrate preparation includes choosing an appropriate material and its crystallographic orientation; cleaning it, often with a diamond powder to abrade a non-diamond substrate; and optimizing the substrate temperature (about 800 °C) during the growth through a series of test runs. The gases always include a carbon source, typically methane, and hydrogen with a typical ratio of 1:99. Hydrogen is essential because it selectively etches off non-diamond carbon. The gases are ionized into chemically active radicals in the growth chamber using microwave power, a hot filament, an arc discharge, a welding torch, a laser, an electron beam, or other means.
During the growth, the chamber materials are etched off by the plasma and can incorporate into the growing diamond. In particular, CVD diamond is often contaminated by silicon originating from the silica windows of the growth chamber or from the silicon substrate. Therefore, silica windows are either avoided or moved away from the substrate. Boron-containing species in the chamber, even at very low trace levels, also make it unsuitable for the growth of pure diamond.
Detonation of explosives
Electron micrograph (
) of detonation nanodiamond
Diamond nanocrystals (5 nm in diameter) can be formed by detonating certain carbon-containing explosives in a metal chamber. These nanocrystals are called “detonation nanodiamond”. During the explosion, the pressure and temperature in the chamber become high enough to convert the carbon of the explosives into diamond. Being immersed in water, the chamber cools rapidly after the explosion, suppressing conversion of newly produced diamond into more stable graphite. In a variation of this technique, a metal tube filled with graphite powder is placed in the detonation chamber. The explosion heats and compresses the graphite to an extent sufficient for its conversion into diamond. The product is always rich in graphite and other non-diamond carbon forms and requires prolonged boiling in hot nitric acid (about 1 day at 250 °C) to dissolve them. The recovered nanodiamond powder is used primarily in polishing applications. It is mainly produced in China, Russia and Belarus and started reaching the market in bulk quantities by the early 2000s.
Micron-sized diamond crystals can be synthesized from a suspension of graphite in organic liquid at atmospheric pressure and room temperature using ultrasonic cavitation. The diamond yield is about 10% of the initial graphite weight. The estimated cost of diamond produced by this method is comparable to that of the HPHT method; the crystalline perfection of the product is significantly worse for the ultrasonic synthesis. This technique requires relatively simple equipment and procedures, but it has only been reported by two research groups, and has no industrial use as of 2012. Numerous process parameters, such as preparation of the initial graphite powder, the choice of ultrasonic power, synthesis time and the solvent, are not yet optimized, leaving a window for potential improvement of the efficiency and reduction of the cost of the ultrasonic synthesis.
Traditionally, the absence of crystal flaws is considered to be the most important quality of a diamond. Purity and high crystalline perfection make diamonds transparent and clear, whereas its hardness, optical dispersion (luster) and chemical stability (combined with marketing), make it a popular gemstone. High thermal conductivity is also important for technical applications. Whereas high optical dispersion is an intrinsic property of all diamonds, their other properties vary depending on how the diamond was created.
Diamond can be one single, continuous crystal or it can be made up of many smaller crystals (polycrystal). Large, clear and transparent single-crystal diamonds are typically used in gemstones. Polycrystalline diamond (PCD) consists of numerous small grains, which are easily seen by the naked eye through strong light absorption and scattering; it is unsuitable for gems and is used for industrial applications such as mining and cutting tools. Polycrystalline diamond is often described by the average size (or grain size) of the crystals that make it up. Grain sizes range from nanometers to hundreds of micrometers, usually referred to as “nanocrystalline” and “microcrystalline” diamond, respectively.
Synthetic diamond is the hardest known material, where hardness is defined as resistance to indentation. The hardness of synthetic diamond depends on its purity, crystalline perfection and orientation: hardness is higher for flawless, pure crystals oriented to the direction (along the longest diagonal of the cubic diamond lattice). Nanocrystalline diamond produced through CVD diamond growth can have a hardness ranging from 30% to 75% of that of single crystal diamond, and the hardness can be controlled for specific applications. Some synthetic single-crystal diamonds and HPHT nanocrystalline diamonds (see hyperdiamond) are harder than any known natural diamond.
Impurities and inclusions
Every diamond contains atoms other than carbon in concentrations detectable by analytical techniques. Those atoms can aggregate into macroscopic phases called inclusions. Impurities are generally avoided, but can be introduced intentionally as a way to control certain properties of the diamond. Growth processes of synthetic diamond, using solvent-catalysts, generally lead to formation of a number of impurity-related complex centers, involving transition metal atoms (such as nickel, cobalt or iron), which affect the electronic properties of the material.
For instance, pure diamond is an electrical insulator, but diamond with boron added is an electrical conductor (and, in some cases, a superconductor), allowing it to be used in electronic applications. Nitrogen impurities hinder movement of lattice dislocations (defects within the crystal structure) and put the lattice under compressive stress, thereby increasing hardness and toughness.
Unlike most electrical insulators, pure diamond is a good conductor of heat because of the strong covalent bonding within the crystal. The thermal conductivity of pure diamond is the highest of any known solid. Single crystals of synthetic diamond enriched in 12
(99.9%), isotopically pure diamond, have the highest thermal conductivity of any material, 30 W/cm·K at room temperature, 7.5 times higher than copper. Natural diamond’s conductivity is reduced by 1.1% by the 13
naturally present, which acts as an inhomogeneity in the lattice.
Diamond’s thermal conductivity is made use of by jewelers and gemologists who may employ an electronic thermal probe to separate diamonds from their imitations. These probes consist of a pair of battery-powered thermistors mounted in a fine copper tip. One thermistor functions as a heating device while the other measures the temperature of the copper tip: if the stone being tested is a diamond, it will conduct the tip’s thermal energy rapidly enough to produce a measurable temperature drop. This test takes about 2–3 seconds.
Machining and cutting tools
Most industrial applications of synthetic diamond have long been associated with their hardness; this property makes diamond the ideal material for machine tools and cutting tools. As the hardest known naturally occurring material, diamond can be used to polish, cut, or wear away any material, including other diamonds. Common industrial applications of this ability include diamond-tipped drill bits and saws, and the use of diamond powder as an abrasive. These are by far the largest industrial applications of synthetic diamond. While natural diamond is also used for these purposes, synthetic HPHT diamond is more popular, mostly because of better reproducibility of its mechanical properties. Diamond is not suitable for machining ferrous alloys at high speeds, as carbon is soluble in iron at the high temperatures created by high-speed machining, leading to greatly increased wear on diamond tools compared to alternatives.
The usual form of diamond in cutting tools is micrometer-sized grains dispersed in a metal matrix (usually cobalt) sintered onto the tool. This is typically referred to in industry as polycrystalline diamond (PCD). PCD-tipped tools can be found in mining and cutting applications. For the past fifteen years, work has been done to coat metallic tools with CVD diamond, and though the work still shows promise it has not significantly replaced traditional PCD tools.
Most materials with high thermal conductivity are also electrically conductive, such as metals. In contrast, pure synthetic diamond has high thermal conductivity, but negligible electrical conductivity. This combination is invaluable for electronics where diamond is used as a heat sink for high-power laser diodes, laser arrays and high-power transistors. Efficient heat dissipation prolongs the lifetime of those electronic devices, and the devices’ high replacement costs justify the use of efficient, though relatively expensive, diamond heat sinks. In semiconductor technology, synthetic diamond heat spreaders prevent silicon and other semiconducting materials from overheating.
Diamond is hard, chemically inert, and has high thermal conductivity and a low coefficient of thermal expansion. These properties make diamond superior to any other existing window material used for transmitting infrared and microwave radiation. Therefore, synthetic diamond is starting to replace zinc selenide as the output window of high-power CO2 lasers and gyrotrons. Those synthetic polycrystalline diamond windows are shaped as disks of large diameters (about 10 cm for gyrotrons) and small thicknesses (to reduce absorption) and can only be produced with the CVD technique. Single crystal slabs of dimensions of length up to approximately 10 mm are becoming increasingly important in several areas of optics including heatspreaders inside laser cavities, diffractive optics and as the optical gain medium in Raman lasers. Recent advances in the HPHT and CVD synthesis techniques have improved the purity and crystallographic structure perfection of single-crystalline diamond enough to replace silicon as a diffraction grating and window material in high-power radiation sources, such as synchrotrons. Both the CVD and HPHT processes are also used to create designer optically transparent diamond anvils as a tool for measuring electric and magnetic properties of materials at ultra high pressures using a diamond anvil cell.
Synthetic diamond has potential uses as a semiconductor, because it can be doped with impurities like boron and phosphorus. Since these elements contain one more or one less valence electron than carbon, they turn synthetic diamond into p-type or n-type semiconductor. Making a p–n junction by sequential doping of synthetic diamond with boron and phosphorus produces light-emitting diodes (LEDs) producing UV light of 235 nm. Another useful property of synthetic diamond for electronics is high carrier mobility, which reaches 4500 cm2/(V·s) for electrons in single-crystal CVD diamond. High mobility is favourable for high-frequency operation and field-effect transistors made from diamond have already demonstrated promising high-frequency performance above 50 GHz. The wide band gap of diamond (5.5 eV) gives it excellent dielectric properties. Combined with the high mechanical stability of diamond, those properties are being used in prototype high-power switches for power stations.
Synthetic diamond transistors have been produced in the laboratory. They are functional at much higher temperatures than silicon devices, and are resistant to chemical and radiation damage. While no diamond transistors have yet been successfully integrated into commercial electronics, they are promising for use in exceptionally high-power situations and hostile non-oxidizing environments.
Synthetic diamond is already used as radiation detection device. It is radiation hard and has a wide bandgap of 5.5 eV (at room temperature). Diamond is also distinguished from most other semiconductors by the lack of a stable native oxide. This makes it difficult to fabricate surface MOS devices, but it does create the potential for UV radiation to gain access to the active semiconductor without absorption in a surface layer. Because of these properties, it is employed in applications such as the BaBar detector at the Stanford Linear Accelerator and BOLD (Blind to the Optical Light Detectors for VUV solar observations). A diamond VUV detector recently was used in the European LYRA program.
Conductive CVD diamond is a useful electrode under many circumstances. Photochemical methods have been developed for covalently linking DNA to the surface of polycrystalline diamond films produced through CVD. Such DNA modified films can be used for detecting various biomolecules, which would interact with DNA thereby changing electrical conductivity of the diamond film. In addition, diamonds can be used to detect redox reactions that cannot ordinarily be studied and in some cases degrade redox-reactive organic contaminants in water supplies. Because diamond is mechanically and chemically stable, it can be used as an electrode under conditions that would destroy traditional materials. As an electrode, synthetic diamond can be used in waste water treatment of organic effluents and the production of strong oxidants.
Colorless gem cut from diamond grown by chemical vapor deposition
Synthetic diamonds for use as gemstones are grown by HPHT or CVD methods, and currently represent approximately 2% of the gem-quality diamond market. However, there are indications that the market share of synthetic jewelry-quality diamonds may grow as advances in technology allows for larger higher-quality synthetic production on a more economic scale. They are available in yellow and blue, and to a lesser extent colorless (or white). The yellow color comes from nitrogen impurities in the manufacturing process, while the blue color comes from boron. Other colors, such as pink or green, are achievable after synthesis using irradiation. Several companies also offer memorial diamonds grown using cremated remains.
Gem-quality diamonds grown in a lab can be chemically, physically and optically identical to naturally occurring ones. The mined diamond industry has undertaken legal, marketing and distribution countermeasures to protect its market from the emerging presence of synthetic diamonds. Synthetic diamonds can be distinguished by spectroscopy in the infrared, ultraviolet, or X-ray wavelengths. The DiamondView tester from De Beers uses UV fluorescence to detect trace impurities of nitrogen, nickel or other metals in HPHT or CVD diamonds.
At least one maker of laboratory-grown diamonds has made public statements about being “committed to disclosure” of the nature of its diamonds, and laser-inscribes serial numbers on all of its gemstones. The company web site shows an example of the lettering of one of its laser inscriptions, which includes both the words “Gemesis created” and the serial number prefix “LG” (laboratory grown).
In May 2015, a record was set for an HPHT colorless diamond at 10.02 carats. The faceted jewel was cut from a 32.2-carat stone that was grown within 300 hours.
Traditional diamond mining has led to human-rights abuses in Africa and elsewhere. The 2006 Hollywood movie Blood Diamond helped to publicize the situation. Consumer demand for synthetic diamonds is increasing, albeit from a small base, as customers look for stones which are ethically sound, and are cheaper.
According to a report from the Gem & Jewellery Export Promotional Council, synthetic diamonds accounted for 0.28% of diamond produced for use as gem stones in 2014. Lab diamond jewellery is sold in the United States by brands including Pure Grown Diamonds (formerly known as Gemesis) and Lab Diamonds Direct; and in the UK by Nightingale online jewellers.
Synthetic diamonds sold as jewelry typically sell for 15–20% less than natural equivalents, but the relative price is expected to decline further as production economics improve.
- Diamond simulant
- Diamond enhancement
- List of synthetic diamond manufacturers
- Material properties of diamond
- Shelby Gem Factory
- The Diamond Maker (1895): a short story by H. G. Wells inspired by Hannay and Moissan
- ^ 16 C.F.R. Part 23: Guides For The Jewelry, Precious Metals, and Pewter Industries: Federal Trade Commission Letter Declining To Amend The Guides With Respect To Use Of The Term “Cultured”, U.S. Federal Trade Commission, July 21, 2008.
- ^ Zimnisky, Paul (January 22, 2013). “The state of 2013 global rough diamond supply”. Resource Investor. Retrieved February 4, 2013.
- ^ Tennant, Smithson (1797). “On the nature of the diamond”. Philosophical Transactions of the Royal Society of London. : 123–127. doi:10.1098/rstl.1797.0005.
- Lavoisier (1772) “Premier mémoire sur la destruction du diamant par le feu” (First memoir on the destruction of diamond by fire), Histoire de l’Académie royale des sciences. Avec les Mémoires de Mathématique & de Physique (History of the Royal Academy of Sciences. With the Memoirs of Mathematics and Physics), part 2, 564–591.
- Lavoisier (1772) “Second mémoire sur la destruction du diamant par le feu” (Second memoir on the destruction of diamond by fire), Histoire de l’Académie royale des sciences. Avec les Mémoires de Mathématique & de Physique, part 2, 591–616.
- ^ As early as 1828, investigators claimed to have synthesized diamonds:
- Procès-verbaux des séances de l’Académie (Académie des sciences) Academy of Sciences], November 3, 1828, volume 9, page 137: “Il est donné lecture d’une lettre de M. Gannal qui communique quelques recherches sur l’action du phosphore mis en contact avec le carbure de soufre pur, et sur le produit des ses espériences qui ont offert des propriétés semblables à celles de particules de diamant.” (There was given a reading of a letter from Mr. Gannal, who communicated some investigations into the action of phosphorus placed in contact with pure carbon disulfide, and into the product of his experiments, which have presented properties similar to those of particles of diamond.)
- “Artificial production of real diamonds,” Mechanics’ Magazine, (278): 300–301 (December 6, 1828).
- Procès-verbaux des séances de l’Académie (Académie des sciences), November 10, 1828, volume 9, page 140: “M. Arago communique une note de M. Cagniard de Latour, par laquelle ce physician déclare qu’il a de son côté réussi à faire cristalliser le carbone par des méthodes différentes de celles de M. Gannal, et qu’un paquet cacheté qu’il a déposé au Secrétariat en 1824 contient le détail de ses premiers procédés. M. Arago annonce qu’il connaît une autre personne qui est arrivée à des résultats semblables, et M. Gay-Lussac fait connaître que M. Gannal lui avait parlé depuis plus de huit ans de ses tentatives.” (Mr. Arago communicated a note from Mr. Cagniard de Latour, in which this physicist states that he has, on his part, succeeded in making carbon crystallize by methods different from those of Mr. Gannal, and that a sealed packet which he deposited with the Secretary in 1824 contains the details of his initial procedures. Mr. Arago announced that he knew another person who had arrived at similar results, and Mr. Gay-Lussac announced that Mr. Ganal had spoken to him eight years ago about his attempts.)
- Procès-verbaux des séances de l’Académie (Académie des sciences), December 1, 1828, volume 9, page 151: “M. Thenard donne lecture du procès verbal des expériences faites le 26 Novembre 1828 sur la Poudre présentée comme diamant artificiel, par M. Cagniard de Latour.” (Mr. Thenard gave a reading of the minutes of experiments made on November 26, 1828 on the powder presented as artificial diamond by Mr. Cagniard de Latour.)
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Here’s a full-length Diamond-level game of what to expect.
Pros and Cons
- Gets exponentially stronger as the match continues
- Prevents damaged opponents from fleeing fights
- Reliably farms creeps from a distance
- Able to duel anyone late game
- Powerful objective defender
- One of the best siegers in the game
- Atrociously weak early game
- Has low mobility
- Difficult laning phase
- Incredibly incredibly squishy
- Pathetic objective controller
- Neverending greed for mana
The Barrage Limit
Distributing Death in Moderated Concentrations
This is a term that will be repeated throughout the guide several times, and for good reason! It’s one of the most fundamental parts of playing Kog and impacts laning, teamfighting, and defending.
The ultimate’s mana cost goes up almost exponentially. Shooting 1 ult is a pitiful 40 mana, but shooting a full barrage of 10 bullets requires an enormous 2,200 mana.
This poses a problem. Continuing to fight requires constantly shooting, but constantly shooting drains mana. To maximize your time poking, you need to shoot just enough that your mana regen will have replenished more than the mana expended when your artillery stacks reset to 0, accounting for ult cooldown.
Or, more simply:
If you regenerate 120 mana in 12 seconds, then you can consistently shoot 2 bullets (120 mana’s worth).
If you regenerate 240 mana in 14 seconds, then you can consistently shoot 3 bullets (240 mana’s worth).
The number of bullets it takes to break equal with your mana regen is known as the Barrage Limit. The two examples above have Barrage Limits of 2 and 3.
It’s a bit more than 10 seconds because the ult does have a 1-2 second cooldown between shots, and there’s also time needed to line up the next shot.
Your Barrage Limit can be considered your guaranteed bullets. The rest of your mana bar is considered reserve bullets.
A final note: the Barrage Limit is not an exact science. You’ll often find that you will lose 20-60 mana per barrage even if you stay at the Barrage Limit. However, it functions as a serviceable estimate. You can find out how to increase the barrage limit later in the guide.
Making the Rain Have Pain
There are a few extremely important, unintuitive things to keep in mind about AP Kog’maw for this guide to be of maximum effectiveness.
Scroll to the bottom of this section if you want the short version.
Kog benefits little from AP
AP Kog’maw is largely a misnomer. Unless you’re at full build, your AP levels will hover around 180 AP even 40 minutes into the game. Living Artillery has a fairly unimpressive 0.25-0.5 scaling on it, which makes it an underwhelming choice compared to simply increasing the Barrage Limit.
This isn’t to say Kog has bad ratios overall. The other abilities have fairly decent or even impressive attached ones. But AP Kog’maw is not dangerous due to their basic spells. If you’re looking for a mid-range AP champion, there are a wealth of others with significantly better damage, mobility, and utility.
AP Kog’maw is dangerous because they abuse the range and base damage of the ultimate. The ultimate, at max rank, can dish out a whopping 360 magic damage. Landing just two hits in one second with this is enough to deal more damage than almost any other ultimate in the game. At a 1800 range.
However, your ability to consistently abuse this base damage is limited by the Barrage Limit. To take maximum advantage of spell penetration requires a high Barrage Limit.
Kog’s Offensive Power Scales With Mobility
Hitting a person in a teamfight with one Living Artillery is easy. Hitting them reliably again is hard. The ultimate is designed to be entirely avoidable. Even if a champion is directly at the center of the ultimate, they are almost guaranteed to be able to run out of the AOE. If someone is running from you, they will outrun you as the casting time of the Ult prevents you from catching up.
This means a person getting hit multiple times is messing up, and you never want to fully rely on strategies that depend on your opponents just messing up.
To reliably chain ults on fighting opponents requires CC. To reliably chain ults on running opponents requires having more movement speed than the runner. Reliably chaining ults dramatically increases fighting power, meaning mobility indirectly increases Kog’s offensive potential. However, when you hit the point where you can outrun opponents while ult’ing, any additional mobility encounters diminishing offensive returns.
Kog’s Offensive Power Scales With Mana
As Kog gets more mana and mana regen, the Barrage Limit increases.
Every time you increase your Barrage Limit, you effectively increase your consistent damage output. Multiply the ult’s base damage by the Barrage Limit, and this is how much damage you can spread out in the ~12 second window before the ult resets the mana cost.
Each additional increase to the Barrage Limit is worth less than the one before. Having a Barrage Limit of 2 is twice as much damage compared to a Barrage Limit of 1, but increasing the Barrage Limit from 3 to 4 is only a 33% increase.
Unfortunately besides Tear, the mana regeneration options for mid lane are inordinately expensive. Mana regeneration needs to be sought out in other ways, primarily through killing Aqua Dragons and Blue Buff.
tl;dr: Kog’s Build Priorities
The summary of everything above is that you should build Kog to take maximum advantage of the high base damage and range. The core philosophy behind playing AP Kog is:
“One more ult.”
One more Ult per teamfight, one more Ult on running opponents, one more Ult when defending.
This means the stats Kog generally wants more than anything else are:
Magic Penetration > Mana > Mobility > Survivability > Cooldown Reduction > AP
This guide is built around this mantra.
Take note this means you won’t necessarily have a lot of early-mid burst damage. But this is okay because you are a sustained damage champion!!! Always remember this. You will often get comments like “you don’t do any damage.” This is because it is extremely easy to overlook sustained damage compared to burst damage. You will almost always have one of the highest damages dealt in each match, so ignore these comments and focus on your aim.
Masteries and Runes
Referring back to earlier priorities, it’s mandatory to reach for the meditation talent within Cunning. The mobility and defensive bonuses from the Resolve tree are too minimal to care for. This means the remaining points must now be dedicated to maximizing offense. Both trees offer similar levels of magic penetration, meaning the choice boils down to the Keystone Mastery.
Though a tricky choice, it ultimately goes to Thunderlord’s Decree instead of Deathfire’s Touch simply because AP Kog has too little AP for most of the game to make very good use of Touch. Additionally, the burn of Liandrys nearly auto-activates Thunderlords.
- Just clicking on your opponent will often be sufficient to kill them even if they’re trying to juke the passive through bushes
- If you are running and about to die anyway, turn around. Fight. The passive may be able to turn a fruitless run into a revenge kill.
- Shreds a significant amount of armor and magic resist
- Use it when tanks commit to fights in the middle of your team
- After Rylais, it functions as an excellent peel tool
- Useful for farming, but little else for most of the match
- If you’re in range to autoattack, you’re probably too close to the fight.
- Late game, it can win you most duels and is amazing shred against tanky divers after applying Caustic Spittle
- Does not proc Rylai’s slow
- Your most reliable farming spell
- The slow scales with the level of the spell
- Fairly respectable damage late-game against bunched opponents when not peeling with it
- The keystone of AP Kog’maw
- Every level-up doubles Kog’s power and heavily increases range.
Void Ooze has the most range, damage, and utility of all the basic spells, making it the first to be maxed.
Being in range to autoattack is too reckless as AP Kog, making the Q second to max.
It’s one thing to say that AP is really poor on AP Kog, it’s another thing to prove it. So let’s do that, by first discussing damage efficiency, not to be confused with gold efficiency!
Gold efficiency only tells you how much gold an item theoretically costs while ignoring AP scalings, true damage, and damage patterns. This makes it a decent tool, but we can do better.
By using a calculator I’ve created for AP Kog’maw, it is possible to find the total damage of any set of spells / autos, which is divided from the gold spent. The Gold Spent For Each Point of Damage, also known as Gold/DMG, also known as damage efficiency.
This metric is significantly more useful; Rabadons may give the most raw damage, but it is also an insane amount of gold. What if Sorc Shoes provide half the damage at a third of the cost? Then Sorcs would be the better bang for buck.
The results? Magic penetration is absolutely amazing. There is no raw AP item that provides more bang for buck than magic penetration items on AP Kog’maw, including a second Sorcerer’s Shoes!
The following item choices were then judged on the damage efficiency metric.
At this point in the build, you may want to consider a defensive option before gathering more offensive power. Here are your choices.
|Because AP Kog barely autoattacks, Dead Mans functions as a permanent 60 MS boost along with some nice bulk. Use if the opponents are primarily physical-damage-based and you need the bulk to survive a physical assassin|
|You can’t fight if you’re dead. Magical assassins have little limitation reaching Kog, but a Banshees protects from their critical burst spell handily. It also shuts down several flash-combos that normally would jeopardize Kog’s position. Use if the opponents have a magical damage assassin or have a long-range flash-combo that is pivotal to reaching you.|
|Extremely niche, but powerful. Your range ensures that you can easily and safely proc the passive. Use when against teams with several sources of healing.|
You won’t always need a defensive choice. Back to our regularly scheduled killing.
|The second most damage-efficient spell penetration item for AP Kog’maw. However, a bit of practicality does intervene here: after Liandrys, Kog’maw already has 48 magic penetration. This is essentially true damage to squishies, making Void Staff provide no extra penetration. Build it if enemies are starting to ramp up more than 72 MR|
|Not technically as damage-efficient as Void Staff, but when you’re already dealing true damage to the enemy, it’s still a better choice. Aether Wisp is the preferred component if running out of slots, even if you can afford Needlessly Large Rod. Build it if enemies have 48 or less MR.|
|Wait don’t we already have sorc shoes? Yes. And despite this, magic penetration is just so good on AP Kog’maw that it has the same damage efficiency as Ludens and Void Staff. It’s not as slot efficient, but sometimes you need damage in a pinch, and it fits in a nice sweet spot between Void Staff and Luden’s. Build it if enemies have more than 48 MR, but less than 72, and you need immediate damage.|
|Damage efficiency stops mattering when you can’t spend gold on anything else. The shield is okay too. Build it as a last item|
|The common theme of this guide is that AP really is not that valuable on AP Kog. Rabadons exemplifies that; it is less damage-efficient than Liandrys, Void Staff, and even a second Sorceror Boots. It’s a terrible buy in all practical scenarios.|
|The second common theme of this guide is that mobility is really valuable on AP Kog. Zhonyas asks you to sacrifice mobility to go into a statis, during which you’ll almost certainly be surrounded and killed. Deadmans provides sufficient protection without compromising your mobility.|
|If you’re in range to autoattack, you’re too close to the fight. The mobility may be nice, but Dead Man’s would be better for the purpose while also increasing the offensive potential of the ultimate by far more.|
|What’s wrong with more mobility? Nothing necessarily, except that with movement speed quints and the utility speed bonus, Swiftness hits the hard cap of movement speed, making it grant barely any more than Sorceror Boots but without granting the spell penetration to abuse the ult’s base damage.|
| This one is tricky. Mana? Surviability? It contends with Tear of Goddess well. But then, it’s not quite fair to compare a 700 gold item to a 2800 gold one. Rod of Ages is a classic case of an item that sounds good on paper, but is awkward in practice.
Building Catalyst takes much longer than Tear early game, delaying Kog’s already-expensive build even more. Catalyst isn’t the only hurdle. Its position in the build order is awkward too. Finishing Rod after Rylais means you won’t have it fully stacked until 30 minutes into the game. Finishing Rod before Rylais requires a stupid amount of money that could have been instead put into a Tear + double Ruby Crystal combo.
Even just upgrading Tear into Archangel’s Staff grants almost all the same stats, taking into account Seraph’s shield active which you quickly stack enough to get.
Doesn’t Have a Nice Ring to it
This start may initially seem confusing. Why no potions? What about Doran’s Ring?
The Problem with Potions
First, potions are not free. Each potion costs 50 gold, which is about 3 minion’s worth. Therefore, to have potions worth their cost, you need to get 4 more minions that you otherwise would not have been able to get. Otherwise, you are breaking even or worse, and the only gain is exp.
Second, Kog is so squishy that you can’t freely farm. Any decent opponent is going to be constantly harassing you away every time you try to move in to autoattack the minions. If you’re in range to be getting hit at all, you are not far enough. In addition, Kog’s early game is so weak that attempting to trade with people is an attempt in futility. You won’t be getting kills pre-6 unless your opponent is badly messing up.
These two facts combined mean that if you buy health potions, you would have to put yourself in poke-range and yet still manage to get 4 more minions that otherwise would have been lost. This doesn’t happen. Your autoattacks are too weak, your early range too limited, and your spells too infrequent to get 4 extra minions while standing in range of being hit.
Potions may serve useful when learning AP Kog, but they’re a needless crutch once you become proficient at farming from max range, especially because optimal play guarantees that you’ll run out of mana way before running of HP, even assuming you get hit occasionally.
The Problem with Doran’s Ring
When you buy Doran’s Ring, you get it knowing that you’ll eventually have to sell it. The amount of money lost from buying and then selling it is 240 gold, or about 13 minions.
To make the Ring worthwhile requires ultimately getting 14 more minions that otherwise would have been lost.
The AP component of Dorans is already negligible. Void Ooze, your primary laning ability, only receives a pitiful 7 damage increase. The AP increase will largely not increase your farming potential. AP also has little benefit for AP Kog later down the road.
Sapphire Crystal gives 250 mana. A long estimate for the first recall to refill on mana happens about 5 minutes into the laning phase. At level 5, Faerie Charm will provide 0.54 mana per second, for a total of 162 mana over five minutes. In total, the pair grants 412 mana over five minutes.
By comparison, Doran’s Ring regenerates 1.08 mana per second, for a total of 324 mana over five minutes. Hitting 80% of the 69 spawned minions will result in 220 more mana, for a grand total of 544 mana.
The question is now can you get 14 more minions that otherwise would have been lost with 60 more HP and 130 more mana compared to the Crystal start? Probabbblyy not.
130 more mana is barely one more Void Ooze, which nets 3 minions in a great case scenario. 60 more health might give one more auto of free reign, which is about 1 minion. That’s looking at maybe 6 or 7 minions that otherwise would have been lost. At the cost of now having to delay the Tear rush and the Ruby Crystals.
Dorans is built with a purpose, and that purpose is to get an edge for the laning phase. For AP Kog, who doesn’t care about trying to win the laning phase, it isn’t as smart an investment compared to many other laners.
The Problem with Refillable Potion
As with Doran’s, you buy knowing you sell it. 70 lost gold, so you need 5 more minions that would have otherwise been lost.
This sounds reasonable. That even sounds completely doable. But it’s important to see what is being lost in exchange for it: the mana from faerie charm.
As mentioned earlier, will regenerate 162 mana over five minutes. With Void Ooze and Barrage, that can earn about 4 or 5 minions. Really what is being asked is: can you get 11 minions that otherwise would have been lost with the extra health with refillable compared to the charm start? Actually… probably yeah. Refillable ain’t too shabby. I wouldn’t recommend against it.
But Here is where experience must simply take hold: unless messing up, I always run out of mana before I run out of HP. This means mana is a much bigger limiter on the number of minions able to be farmed rather than HP. I wouldn’t fault anyone for going refillable flask, and for most cases it is suitable. However, proper experience makes it a needless investment, one that extra mana is better able to suit.
The Remaining Build Order
Priorities in Practice
beginning of the guide
, we established the priorities Kog has.
Magic Penetration > Mana > Mobility > Survivability > Cooldown Reduction > AP
Additionally in the Items section, we evaluated the damage efficiency (not cost efficiency!) of various AP items by using our AP Kog’maw Damage Efficiency Calculator (TM) The build order is the culmination of all that.
In order, get > > > > > > You can consider getting a single Ruby Crystal if you’re not having a difficult matchup, but two Rubies makes it incredibly difficult for enemies to one-shot you, and they build into Rylais and Guise; good combo!
Then, consider picking up a situational item
And follow up by completing
Refer to the Items section to determine when to build each one.
Ludens for 48 or less MR.
Void Staff for 72 or more MR.
Sorcerer Shoes for between 48 and 72 MR, and for immediate damage.
Yes, that is a second Sorcerer’s Shoes; read the Items section for the math! Magic pen is just that good on AP Kog.
One final item
A Note About Components
Many of the items in this set have raw AP components like Blasting Wand.
If you have a choice between using a final slot for a raw AP component vs. a control ward, go with the control ward.
AP is a poor value choice on AP Kog, and stronger vision is more meaningful than a pittance of extra damage on the ult.
That’s Off the Chain
When Kog has Rylais, they gain access to one of their most powerful and flashy tricks: chaining.
Chaining is using CC to ult a target back-to-back with Living Artillery. Normally, chaining is hard. An opponent is able to dodge Living Artillery simply by stepping outside of the landing spot. But with Rylais, if Kog lands just one artillery, it almost guarantees that the next artilleries will land.
After landing the ult, continue aiming the ult a little ahead of the opponent’s running direction. This forces two decisions: either they get hit by the ult and open themselves up to the next ult chain, or they momentarily stop or sidestep.
In teamfights, an opponent is often able to escape chains pre-16 just by getting outside the range of subsequent artilleries, making chaining difficult. After 16, successful chains are extremely feasible and can kill or seriously cripple a carry before the fight even starts.
Outside of teamfights, chaining is a powerful kill securing tool. After a chain is started, even stopping to dodge the artillery is to Kog’s advantage. A person who has to momentarily stop has put themselves closer to Kog. If they stop sufficient times, Kog will be able to reliably land an ooze-spittle combo, killing wounded opponents almost instantly.
Chain opponents down to secure kills in teamfights or on fleeing opponents.
Stage of the Game
Kog is not defined so much by “early, mid, late” as many other champs as far as their role is concerned. Rather, Kog’s power and presence is dictated by the rank of Living Artillery.
Rank 0 – Feeble Mortar Mimicry
- Unless your opponent screws up, you will not win in CS.
- If you chose to not start potions or Dorans, your effective gold is higher than your CS would imply.
- Conversely, subtract CS from your opponent based on how many potions and Dorans they have.
- Survival is the name of the game
- Don’t bother pushing hard. Your autoattacks are like butter slapping a brick.
- If you die, you weren’t playing carefully enough.
Before you have your ult, you’re fragile and your laning phase should consist of using your spells at maximum range to farm the waves. Void Ooze is the most useful one for this task, as it has longer range than any of your other spells and its AOE is able to take out minions decently. Use the tip of its 1,200 range to farm most of your minions.
Never attempt to trade or poke with the enemy. It doesn’t matter if they’re melee, if they have less range, or even if they’re out of mana. Every spell, every auto should be focused on trying to farm above all else. Your kill potential is fairly nonexistent pre-6. If you think you can kill them by hitting them enough? That’s precisely when everything will start going wrong.
Kog is such an easy target for the jungler to jump on. This is the biggest reason why even poking is fruitless; a competent jungler will take advantage of your vulnerability even if you’re only a quarter of the way down the lane.
Survival is your primary priority. Unless you have a jungler with a mixture of heavy CC and heavy damage, consider informing your jungler to not even gank for you. Kills rarely result unless the jungler has red and you can land a well-timed void ooze or exhaust. But even this opens up the fight to a countergank that is easy to lose.
Your pushing power is stupidly weak. Even two uncontested minion waves won’t bring the tower to half health. It’s not worth the risk unless their jungler is in a different lane.
Get an early control ward and set it up to protect from a jungler tower-dive ambush. Good locations are the bush next to the Raptor camp or the bush across the wall near the tower. If you get jumped under the tower, immediately use exhaust. Literally a life-saver.
Most importantly, when you die, it is 100% your fault. It means you were too far without wards, you were trying to trade, you didn’t dodge enough, or that you got surprised by burst damage. Take every death as a learning experience of what to expect for the future and avoid repeating the same mistake.
Rank 1 – Obnoxious Spittle Tickler
- Prevent opponents from roaming
- Be cautious about roaming; it’s often better to refill on mana
- Force squishy targets back with powerful ooze-ult combos
- If you die during laning, you weren’t playing carefully enough.
- Use your basic spells primarily for their utility
- Poke to deter
The first rank of the ult is your first major power spike, immediately doubling your power. Upon receiving it, your Barrage Limit starts at 1. Shooting even 2 bullets in a row is an easy way to use up your whole mana bar very fast, so carefully consider every time you even want to shoot just twice.
Start warding the center of the enemy’s half of the lane. Your opponent will likely have their ult at this point as well and will often begin roaming as you don’t have the pushing power to take advantage of their disappearance. Putting wards on their side of the lane will ensure that if they begin roaming that you will see which direction they go and your team will have heavy advance notice to get away. You have no pushing power to meaningfully punish roaming opponents
You may often want to chase after roaming opponents, but be aware that they may easily be hiding around a corner or in a bush in ambush, waiting to take advantage of your still-weak power. Alert your team, and be extremely cautious of ambushes if you choose to follow them.
Poking opponents is now possible, but remember your Barrage Limit. Also keep note that your
ult is an excellent tool for farming, especially in conjunction with your ooze. If you use Void Ooze on the caster minions, the execute bonus of the ultimate will become available on them, allowing an instant clear on the minions.
Unless your opponent is very squishy, you should largely be using poke as a form of deterrence rather than a form of killing. Still, a successful ooze-ult combo on an opponent can deal substantial damage so always keep an eye out for chances to land one.
Due to the low barrage limit at this point, and also because Rylais is often not yet completed, chaining is largely not possible.
It’s tempting to roam yourself, but you’re usually better off just being more self-centered and farming up to Level 11. It may be self-centered, but it’s not selfish, because it is the action that maximizes your entire team’s chances of winning.
Rank 2 – Artillery’s Apprentice
- Keep everything constantly warded
- Clear waves instantly and begin pushing and grouping
- Be wary of dash-combos
- Poke to kill
You have hit your second major power spike, doubling your power once again. Now that you are 4x more powerful than at the start, you may begin poking very offensively at the opponents, though always keep mindful your Barrage Limit.
As always, keep the enemy’s side of the lane warded. Your poke may be strong, but you are still extremely susceptible to a good gank.
If you’re 35 CS down at the end of the laning phase, you handled it very well. Your teamfight presence is now massive even with few items. Your Rylais is often finished at this point, and now is the time to start chaining opponents down. Careful however; a wide variety of dash-combos can still reach you even at max range.
Don’t go trigger happy with ultimates. If a fight is about to begin, it is often smart to wait for it so that you can get several execution-enhanced ultimate shots on the enemies.
While you can now chain down fleeing targets reliably, it is difficult to land a long chain during teamfights.
Your ult now functions as a very viable form of killing, though opponents will often still barely get away.
Rank 3 – Ruler of the Acid Reign
- Stay at max range unless you’re cleaning up
- Keep a target locked on and shoot
- Destroy diving opponents
- Poke to win
This is it. If you have made the game go on this long, another 2x multiplier in power. You are now 8x more powerful than you were at the beginning of the game and boy does it ever feel good.
You are now safe from almost every single dash-combo in the game at max range. Unless you are caught off guard due to poor warding, you cannot be reached except by flash-dash combos.
Always remain at max range unless it’s time to clean up, and continue buying constant wards to maximize your safety.
You can safely pick targets every fight who you want to hunt down and chain them to death. Often, just a 3 or 4 artillery chain is enough to send an opposing magician to a quarter health or less for one final execution shot. Pick a target and keep them locked on.
Your dueling potential is extremely strong if you have exhaust up. If the fight is starting to die down, consider getting closer to the fight and pick off the remaining opponents with your basic spells, which now do fairly hefty damage in their own right.
Use your Caustic Spittle to slow down and shred tanks trying to dive into the middle of your team. If combo’d with your spells right after, a few empowered autos is enough to deal insane damage.
Increasing and Exceeding the Barrage Limit
Making Good Impressions
The Barrage Limit has been mentioned several times in this guide, so now is the time to learn how to increase it.
Keep note that the Barrage Limit is not an upper limit on how many times you should shoot in a fight, but a general guide on how to maximize your consistent damage. As you play Kog more, the Barrage Limit starts to become more instinctual.
Barrage Limit starts at 0 and increases depending:
+1 at level 11+
+2 , but +3 after level 11.
+¾, but only when not hit. The highest amount your barrage limit is able to reach is 7
Raj of Barrage
There are times when it’s time to stop holding back and go past the barrage limit. Blow out a full 10-ult barrage and cripple opponents… and yourself.
Realize that pushing past the barrage limit too much will make you useless for any further fighting. As such, it makes sense that the barrage limit should only be exceeded when something can be secured or defended.
That can mean a several things including but not limited to:
- Securing a kill
- Securing an objective
- Securing a kill to secure an objective
- Keeping a small area scouted while taking a ward
- Defending a turret from low-health opponents
- Taking blue buff quickly, since the mana will regenerate
- Holding off opponents from defending an objective when it is almost dead
- Stopping a baron/dragon attempt
- Rushing a baron/dragon where your team plans to peace out after securing it
Knowing when to push the limit is one of the biggest things that separates good AP Kogs from great AP Kogs. Shoot wisely.
They will Looze
Instead of the classic easy/medium/hard difficulties, opponents are classified by what rank of Living Artillery it takes for them to stop being a major threat. The higher the rank, the more difficult, with “Never” being the most difficult. The rank classification is often when previously one-sided fights suddenly start going in favor of Kog’s team.
In addition, each person gets a danger classification: burst, poke, displace, roam. These define how the champion intends to kill you and what is most pertinent to watch out for.
Burst – Attempts to stun and then burst you down from full health
Poke – Attempts to whittle you down with never-ending spells to finish you with a burst
Displace – Attempts to lock or zone you down for other opponents to reach you
Roam – Pushes hard, then roams to take advantage of your weak pushing power.
Most opponents have a non-punishing level 1. Farm freely for the first level.
After opponents cast spells to harass or farm, you have a few precious seconds to move in to farm. Back off before the cooldown ends.
Although enemies can wound you repeatedly, most cannot actually kill you pre-6. Don’t be too concerned about your wounds unless you know the opponent can actually finish you off.
Stay at max range at all times. Pick apart with living artillery before even momentarily considering moving in.
Use Exhaust to successfully duel most opponents after rank 2 of Living Artillery
Listed alphabetically left to right
Rank 2, Burst
One charm, one death. Fighting Ahri pre-6 is fairly anticlimactic, but the instant they hit 6 they will begin to relentlessly Spirit Rush you, especially if the jungler is near. You should be tower-hugging nonstop. A good exhaust at the time of the charm can often guarantee survival.
Rank 1, Burst
Brand’s spells aren’t too hard to dodge, but every one will deal absolutely massive damage. You only have about 3 spells of leeway so be extremely cautious. If you’re stunned even once, you’re nearly assured death.
Rank 3, Burst
Fiddles is unique among opponents in that once you hit 16, you can almost wipe out their relevancy for the rest of the game. Fiddles is obscenely squishy and can’t survive even four ult hits. Aim them as a priority target in every fight, especially since they lack dashes to avoid being chained.
Rank 2, Burst
Fizz is relentless, but they heavily telegraph their attacks before they get their ult. After their ult, they will relentlessly try and land the Chum every single chance possible. Evade Chum, and you’re usually good to go.
Never 4, Displace
Gragas may not have intense burst, but their dash-flash-ult combo can send you careening into the middle of the opponents. It is largely mandatory to get a Banshees if Gragas is on the enemy team.
Rank 1, Poke
Leblanc may initially sound like a difficult matchup, but in reality Leblanc’s pre-6 burst is not especially threatening. After 6, Leblanc is so squishy that even the weak rank-1 Artillery is enough to break their health. Just don’t get (ironically) chained by Leblanc and you’re usually good to go.
Rank 3, Burst-Displace
Lissandra is extremely difficult for Kog to handle as their range is on par even with Kog. Getting entombed a single time is death. They are quite fragile however, and after rank 3 they will never be able to get close again.
Rank 1, Poke-Displace
Though Orianna quickly becomes unable to reach and retaliate against you, their shield makes poking largely ineffective. Keep your mind on farming and don’t get hit by Command: Dissonance, which will chunk you hard.
Never 4, Displace
Jarvan is one of Kog’s most difficult opponents. There is no item that will save Kog from the lockdown of the dash-flash-ult. If you get locked down by the combo, focus your spells and artilleries on slowing down the opponents trying to capitalize on your helplessness. Pray that Jarvan won’t kill you before you escape the walls.
Never 4, Burst
Rengar is quick and their burst is strong. Randuins is practically mandatory if they’re on the enemy team, along with extensive vision wards nearby. Hold onto Void Ooze until Rengar jumps, and then use Ooze to make your escape from their hunting clutches.
Rank 2, Burst-Displace
Fighting Ryze isn’t especially interesting, but note that even without excessive range, one flash-cage is enough to deal massive damage. Focus on farming until even their powerful movement speed isn’t enough to reach you.
Rank 2, Burst-Displace
Syndra is a nightmare to fight pre-rank-2. One stun is all it takes to instantly kill you. However, once you reach Rank 2, the battle becomes one-sided, and you can shoot without retaliation. Later in the match, Syndra is one of the magicians you can effectively duel at close range if you get off an exhaust.
Never 4, Displace
Vi is one of Kog’maw’s most difficult opponents. The dash-flash-ult combo can reach Kog even at their most maximum range and is guaranteed to chunk a significant portion of life. When Vi is on the enemy team, a Banshees is largely mandatory. If Banshees isn’t viable, consider a Randuins.
Rank 2, Poke
Xerath will attempt to hit you down by using their Arcanopulse constantly, and it’s often very difficult to avoid until you get mobility. But while their artillery is strong, your artillery is on par at rank 2, and strictly superior at rank 3. Fight fire with fire.
Rank 2, Poke
Zed is one of Kog’s most difficult opponents. They have a mixture of sustained damage and burst. However, unless they actually hit you with some sustained damage, they can’t successfully follow up with their ult-burst as long as you have a summoner spell up. Fighting Zed thus becomes a battle of sheer dodging tenacity. Avoid shurikens all day.
Rank 1, Poke
Ziggs fights dirty, trying to whittle you down faster than you can whittle them down, especially pre-6. This is a match of sheer dodging tenacity. All of Zigg’s spells are avoidable, but It’s not especially easy and it will be somewhat frustrating. When Ziggs is running toward you, keep distance to avoid the empowered autoattack which hits really hard.
Rank 1, Poke-Roam
Zilean heavily telegraphs their anticipated burst, but well-timed void oozes will prevent them from landing any of their bombs. But when you do get hit, you get HIT. Void Ooze Zilean every time they try to use time warp toward you. Zilean will often roam heavily after pushing against you, so wards are especially important in this matchup.
Tips and Tricks
Truly mastering Kog’maw is perfecting even the littlest of tricks to work massively in your favor. Here’s a list of things to nail to become a master!
Flash ult combo
A difficult trick, but incredibly strong. Opponents will often try to break your chaining by flashing out of it. Flash toward them to immediately close the gap and continue chaining. Also use to get the last bit of distance to snipe a flee’ing opponent, but be wary that if they’re not CC’d, they can dodge the ult and waste your flash.
Checking bushes and objectives with the ult
Living Artillery grants vision on the location it casts on, so use it to see if the roaming mid-laner is trying to ambush you or if the opponents really are at baron.
Use nexus regen to be an ultimate last-ditch defense
The title explains it all. In dire situations where you have to hold off several opponents from nexus turrets, you are able to stand at the edge of the base regeneration and unleash a literally endless stream of bullets. This allows you to become the absolute final line of defense when things are looking grim.
You have two primary burst combos as Kog.
The first is the most common: Ooze-ult. Difficult to anticipate and both reach the end-point around the same time. This is also the combo that lets you clear most minion waves instantly once void ooze is at max rank.
The second is for targets committing: Caustic Spittle, Ooze, Ult, Auto. A committing target can’t avoid the Q, which will amplify the damage from the rest of the combo.
Ult your own location during duels against melee
During duels against melee targets, keep ult’ing at the ground directly underneath yourself. This will guarantee the hit unless the target decides to disengage momentarily, buying valuable time to make distance.
Shoot void ooze in the direction you’re running
When someone is charging toward you, it is tempting to always cast Void Ooze directly at them to slow the charge. However, in many instances, if damage is not of importance, it is better to cast void ooze in the direction you intend to run. This ensures that the enemy has to run across the whole length of the ooze if they want to reach you.
Ooze’ing over minion waves
During laning, you may not be trying to poke opponents down, but incidental damage is always nice. Try to position yourself to hit both the minion and the opponent at the same time.
Aim for the Zhonyas!
Whenever you see someone has gone into Zhonya form, keep your eyes extra peeled on them and try to land an easy ult shot rightttt as the Zhonyas duration ends. Once you get good with the timing of your ult, the Zhonyas form is just a free target.
Tell your team to avoid engaging
The more you can poke before a fight begins, the better. Explicitly tell your team that you need time to poke and to try to stall out engages until you’ve dealt some good damage first.
This guide was a lot of fun to write, and I hope you all have learned everything you would have liked. If you have any questions, leave a comment or drop a line over at twitch.tv/aquadragon33 ! And be sure to check out www.bestbans.com !
May your acid reign be endless.
what is a clarity enhanced diamond and why is it important for you to know about such treatments? Before we answer this question, let’s talk about the value of diamonds which is measured by four characteristics.
These characteristics, also known as the “four C’s” of diamonds” represent the basic attributes that you should always keep in mind when buying a diamond. They are: cut, carat, color and clarity.
Carat only represents the weight of the stone; cut is mainly influenced by the performance of the cutter. The remaining two C’s, color and clarity, are a little different: these represent the material properties of the diamond.
First of All, What is Clarity?
The clarity grade of a diamond represents the material imperfections found on the external surface or the interior of a diamond. The former are also called blemishes. To name a few, these could be scratches on the surface, naturals left behind during the cutting process or hazy looking burn marks that could reduce the light-reflecting capacity of the stone.
The other type of imperfections found inside a diamond are called inclusions. These are could be tiny “specks” of foreign material that obstruct light rays traversing through the diamond or could be huge unsightly splotches like clouds, feathers or cavities that can be observed by the naked eye.
When man is faced with certain problems, the genius in him will spark creative solutions to resolve issues posed by Mother Nature. Lasers were invented in the 1960’s and it proved to be a wonderful engineering tool for many industries. With the ability to be manipulated with pinpoint accuracy, lasers soon found their applications in the jewelry trade as both cutting and enhancement tools.
External Laser Drilling Treatment to Improve Clarity
Laser drilling is a method used in removing inclusions inside the body of a gemstone. A tiny tunnel is drilled into the surface using a laser beam. Through that tunnel, strong acidic chemicals are forced into the opening to dissolve and bleach out the inclusions. Typically, a mixture of concentrated hydrofluoric acid (HF) and sulphuric acid (H2So4) is used.
Profile view of laser drilled diamond showing a tunnel reaching the inclusion – GIA
Generally speaking, laser drilling will not weaken the structural integrity of the diamond to a serious extent. It doesn’t leave any foreign material inside the diamond after the process is performed. When proper drilling techniques are applied, the only observable sign of laser drilling is a microscopical tunnel that reaches the inclusion from the surface.
Now, if you are wondering whether laser drilled diamonds (or any form of enhanced stones) are good buys, let me tell you straight up that you will be sorely disappointed. While these stones may seem “cheap”, the truth of the matter is that 99.99% of clarity enhanced diamonds have terrible quality in terms of cut.
I can tell you that the general consumer is far better off by lowering expectations of the 4Cs and sticking with an untreated diamond. If you are shopping for an engagement ring, James Allen and Blue Nile are reliable vendors with huge inventory bases for any budgets. I recommend you check them out first.
Internal Laser Drilling (Made to Resemble Natural Flaws)
Besides using lasers to create surface reaching tunnels, new methods of internal drilling had also been researched and applied in recent years. Why would people want to use internal laser drilling instead of the traditional laser tunneling? Well, the real reason behind using internal drilling involves a malicious intent to deceive consumers as this treatment is often undisclosed.
You see, internal laser drilling creates many small cleavages with seemingly non-discernible patterns. These “tunnels” serve the purpose of bridging the inclusion to the surface without the use of a direct laser tunnel. The problem with these irregular and worm-like looking channels is that they are purposely made to resemble feathers and passed off as being “natural” flaws.
Artificial treatment that resembles natural inclusions
For this treatment, diamonds with dark inclusions near their surfaces are good candidates for enhancement. After the worm-like channels are drilled, the diamond is subjected to a series bleaching solutions to dissolve the unsightly inclusions.
Black coloration is significantly reduced after treatment
Both dark crystal and feather are no longer that obvious after laser drilling
Source: A New Lasering Technique For Diamond (GIA)
Important note: always ask for a GIA or AGS certificate when buying a diamond. If the jeweler refuses to show you one or tries to promote some other un-heard of reports, it immediately subjects the diamond to suspicion and exercise extreme caution. Besides grade bumping or clarity enhancements issues, the jeweler could be trying to hide some other major issues from you.
“Repairing” the Surface: fracture Filled Diamonds
Although cavities and surface reaching feathers can be removed through polishing, there is a method which does not lead to significant carat weight loss. Fracture filling is the process of inserting glass or liquid glass-like filler material into surface scratches and cracks. Since the filler possesses similar optical properties (refraction) as that of a diamond, the flaws get covered up nicely after the liquid filler is solidified.
Yehuda Diamond Company is the current industry leader who also pioneered fracture filling. Their business model and goal of enabling consumers to purchase larger diamonds at affordable prices has seen some success. Since then, many other companies had tried to emulate their success and started developing their own proprietary method for fracture filling.
Fracture filling can greatly enhance the appearances of feathers and open cleavages – GIA
Now, the problem with fracture filling is that it results in a stone which is no longer made of a uniform material. Despite advances in material science, the filling substance still has vastly different material properties compared to the host diamond. What looks almost perfect after the treatment process might fade with the passing of time. Or worse still, the filling might even fall out in extreme cases.
Typically, when the fillings are exposed to harsh temperatures or strong chemicals like concentrated acids or alkali, the filling would start to degrade or fail. Because of its non-permanent nature, most companies offer lifetime “repairs” for fracture filled diamonds to keep customers happy.
That said, the problem with reworks and a second filling is that it isn’t going to be as good as the first. Also, another limitation of this technique is that once a diamond is filled with a resin, it is impossible to reverse the process completely.
Do note that GIA (Gemological Institute of America) does not grade fracture filled diamonds because they don’t change the appearance of the diamond permanently. C.E. diamonds are usually separately appraised and graded by other labs as they represent a totally different category.
While the motive behind diamond fracture filling sounds good, the huge problem behind these diamonds is that they aren’t cut for light performance. If your priority in getting a diamond lies in the best sparkle and brilliance, I would recommend managing your carat size expectations and head to White Flash or Brian Gavin instead.
Clarity Enhanced Diamonds Pros And Cons
Why do people buy clarity enhanced diamonds? Well, there’s actually no wrong or right answer to this question as it depends on the needs and the type of situation you are in.
For other people who are on a strict budget and yet, would like to purchase a bigger diamond, treated diamonds offer an alternative method to do that without breaking the bank.
For the jewelers, clarity enhancements improve the prospects of selling a severely flawed diamond as the stone now has a better visual appeal. From a business perspective, getting a severely included diamond treated and selling it at a lower cost makes more sense than having it remain stagnant in the inventory.
The Bad Vibes of Clarity Enhanced Diamonds
If you are kept up to date with the latest jewelry industry news, you will realize that clarity enhanced diamonds had received a lot of negative attention recently.
The main reason behind the negativity largely stems from people who found out they had been duped into buying an enhanced diamond at the point of sale. Even though jewelers are required by law to fully disclose any clarity enhancements to the consumer, there are many rogue jewelers who intentionally hide these details in order to make a sale. That’s why you have to be extremely careful and knowledgeable when buying such diamonds.
Ultimately, you have to make the decision for yourself. If you are buying a diamond for practical purposes and don’t have a huge budget to work with, a clarity enhanced diamond might be a viable option for consideration. However, if it comes to buying diamonds as a form of investment or for light performance, untouched natural stones are still the best choice.
I personally think that clarity enhanced diamonds are not worth the money and trouble to buy. If you are on a budget, consider buying eye-clean diamonds with a lower clarity grade instead. In this regard, I highly recommend James Allen as their 360° videos can enable you cherry pick a great diamond that’s eye clean. Feel free to reach out to me if you need help in choosing a diamond.