High-quality large diamond crystals

High-quality, large, type IIa diamond crystals up to 8 carats (similar to 10 mm across) have been successfully synthesized by a temperature gradient method at high pressure and temperatures. The synthetic type IIa diamonds contain less than 0.1 ppm chemical impurities and few inclusions, having no absorptions due to impurities. They also have very high crystalline quality with considerably less residual strain and fewer crystal defects than natural diamonds or conventional synthetic diamonds. Considering these outstanding features, the high-quality, large, synthetic type IIa diamonds may be applied to a wide range of industrial and scientific uses such as monochromators, optical parts, high-pressure anvils, and so on.