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History of CVD diamond synthesis So-called CVD diamond is a natural diamond polished stone as stone, using high-purity methane, and hydrogen, nitrogen and other gases aided, in a special oven at high pressure, with diamond-like carbon in methane molecules accumulate on the diamond stone, through layers of hyperplasia, can form up to 10 carats of transparent diamond. This artificial "grow up" diamond, began to appear as early as 50 's of last century, is widely used in industry. Now part of high quality CVD diamond, was taken to simulate natural diamonds. 1953 first synthetic diamonds in Switzerland ASEA company trial success, followed by United States, and Japan and the United Kingdom, and Russia, and other countries have succeeded in synthetic diamonds. 1961 Japan a diamond synthesized at the time the largest, 3.5 CT;1970-year United States GE synthetic gem-quality diamond for the first time, but the color is yellow; 1988 United Kingdom synthesis of the De Beers company weighs 11.14 CT, pale yellow, Crystal diamond octahedron distortion in 1990, 14.2-Carat diamonds of high quality single crystals synthesized. There are synthetic diamonds on the market mainly is pale yellow, granulated diamond, there are colorless or blue synthetic diamonds, but the latter is very difficult to synthesize, cost is very high. Differences in CVD diamond synthesis and natural diamonds Output of synthetic diamonds and natural diamonds have some differences in physical properties, the difference is shown in table The difference between natural diamonds and synthetic diamonds. jpg Attached: recently on synthesis diamond entered city market news great hurt has general consumers purchased diamond of enthusiasm, is worried himself purchased of diamond is synthesis of, actually is no necessary worried, because gem level synthesis diamond in Shang century 90 generation has entered market, not news, detection method not difficult, in enough buy Shi must to understanding diamond 4C related knowledge, best in funding letter high of businesses, and to attached certificate is security of. Don't go to overseas residents. Characteristics of CVD diamond synthesis CVD synthesis of high net (IF, VVS, VS etc), color (d, e, f, and so on) of diamonds, with brownish-yellow, blue, pink, etc, can also be irradiated into a green, black and pink. Correspond to three types: synthesis of high purity, n-doped and b-doped diamond. A ... strong orange-red fluorescence (SWUV), shortwave are stronger than long wave. B. growth-related structural characteristics-orthogonal observed under polarized light. Abnormal are densely punctate or linear-birefringence (cathode glow or Diamondview-ultra short wave fluorescent pattern), HPHT Sha-bell-shaped pattern with straight sets of cross linear patterns. cheap pearl jewelry， jewelry wholesale suppliers Pearl jewelry wholesale