What is CVD and HPHT?

At present, there are two main techniques for growing diamonds, one is high temperature and high pressure (HPHT diamond) and the other is chemical vapor deposition (CVD diamond). The diamonds cultivated by both methods have the same appearance and properties as natural diamonds. And can be issued in the GIA, IGI, HRD and other authoritative international diamond identification agencies to develop diamond grading certificates. The bred diamonds use small diamonds as “seeds” to simulate the growth environment of natural diamonds through technical means, so that the carbon atoms in the “nutrient” gradually adhere to the diamond seeds, so that the diamond seeds grow into larger diamond crystals. The whole cultivation process is very green, so the word “planting” diamonds is very appropriate.

HPHT is the abbreviation of high temperature and high pressure. Its purpose is to change or improve the natural color of certain kinds of diamonds and make them present more valuable colors.
Generally speaking, it can be upgraded to 4-6 levels. However, not every diamond can be treated by this technology. It must be J-colour or above, with no impurities and high purity. When processing, the results cannot be predicted.

At the same time, diamonds processed by HPHT may be darkened or changed to become color diamond grade.

Diamonds synthesized by chemical vapor deposition are referred to as CVD diamonds. This chemical synthetic diamond is very similar to natural diamond, and it is difficult to distinguish it from natural diamond only by naked eyes. After being detected by Diamond View, blue-green fluorescence and blue phosphorescence can be seen, and the growth texture with the characteristics of synthetic method can be seen.