The other kind lab grown diamond is CVD diamond, which is grown by chemical vapor deposition method. What CVD method grows always is large and ultra large size CVD diamond.
Single crystal CVD diamond was developed from the end of 1990. Till the beginning of 2000, Element Six, Carnegie Institute, Apollo got success, but still couldn’t do market sales. In 2012, Singapore IIa company has used MP CVD to get colorless gem-quality CVD diamond for commercialization, market selling price to 2/3, 1/2, even 1/3 of same grade natural diamond. Single crystal gem-quality CVD diamond is a quite small fraction of its application, which has wider and more important utilization in the aspect of optics, chemical, thermology etc.
There are three kinds of CVD reactor machine: 1) Hot Filament; 2) DC Arc Jet; 3) Microwave Plasma. To grow single crystal CVD diamond, MP reactor is always the option. Throughout the world, there are over 2000 sets CVD machine under working, including India over 800 sets, and more under fast installation as 2020 is the golden year of CVD diamond (Coronavirus may have limit effect). It is expected till 2022, there are over 6000 sets, including China over 2500 sets. CVD diamond is the future.
As jewelry purpose, since lightbox launched $800/ct promotion, CVD diamond market competition has been becoming fiercer and fiercer. Thus, to take a place fast in the lab grown diamond market among millennium, how to control CVD diamond growing cost is increasingly vital. Generally to grow colorless CVD diamond, it takes around 250 hours, which means high production cost. So it is needed to shorten growing period to decrease cost. That’s why it is brought CVD growing diamond with HPHT annealing (treatment) is the alternative. With CVD growing light brown(LB)/ light coffee(LC)/ dark brown(DB) color, high pressure high temperature(HPHT) treatment is used to get colorless quality diamond within 30mins.