In the 1990s, chemical vapor deposition (CVD) was used to synthesize diamond films, which were deposited on solid-phase substrates to form polycrystalline films of
diamond for industrial use. 2003 saw the synthesis of gem-quality single crystals by Apollo in the USA, and commercial production began. More recently, the
Geophysical Laboratory of the Carnegie Institution of Washington, USA achieved a CVD synthesis rate of 100μm/h to produce a 10ct, half-inch thick single-crystal
diamond. To further increase the size of synthetic diamond crystals, it is possible to grow colorless diamond single crystals in three dimensions at the inch scale
(approximately 300ct) by sequentially growing them on six faces of the diamond substrate using CVD. High-pressure, high-temperature heat treatment has also been
found to improve the color and hardness of synthetic CVD diamonds.
*One carat is equal to 0.2grams.
*The waist diameter of the diamond will be affected by the cutting method and proportion. So the same weight diamonds may have different waistlines.