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Gemesis Inc., now known as Pure Grown Diamonds,〔 is a privately held company located in New York City, NY. The corporation grows synthetic diamonds using proprietary technology. Gemesis has the world's largest facilities for both the high pressure–high temperature (HPHT) and chemical vapor deposition (CVD) diamond production methods. Using these methods, Gemesis has produced high-quality colorless and fancy color diamonds that have been offered for sale at 20–30% lower prices than mined natural diamonds of similar quality (and, from some suppliers, lower prices than that). Gemesis is the principal producer of gem-quality lab-created diamonds and jewelry. The company was renamed as Pure Grown Diamonds in June 2014.〔〔 Gemesis started marketing its diamonds by cutting and polishing them and then selling them to jewelry retailers on the wholesale market. In 2012, the company began also selling polished diamonds and diamond jewelry directly to consumers through its website. ==Production process== In the company's HPHT diamond-growing method, carbon, in graphite form, is placed in a cylindrical "core". A tiny seed diamond is placed at the bottom of the cylinder. The graphite is subjected to extreme pressure, 850,000 lbf/in² (5.9 GPa) and temperature, 3000 °F (1600 °C) for four days. During the period, the carbon atoms within the molten metal crystallize on top of the seed diamond. A yellow gem quality diamond up to 3 carats (600 mg) in size grows inside the resolidified metal cylinder. The metal cylinder is then dissolved in mild acid and the diamond crystal is extracted. With the addition or elimination of certain impurities under controlled conditions, diamonds of various color can be produced. Since nitrogen is abundant in the atmosphere, the HPHT process is more likely to produce bright yellow diamonds than any other color (although natural yellow diamonds often have higher value than white diamonds). The yellow tint occurs when approximately five out of each 100,000 carbon atoms in the diamond crystal lattice are replaced with nitrogen atoms. Available in the purest Type IIa colorless and rare fancy yellow colors, the company's diamonds have the same cut, color and clarity, as well as identical chemical, optical and physical characteristics as the highest-quality mined diamonds. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Gemesis」の詳細全文を読む スポンサード リンク
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