Lab-grown diamonds are real diamonds, this is recognized worldwide, GIA and IGI have also been able to issue the corresponding laboratory-grown diamond certificate. The grading content is exactly the same as the natural diamond, including the complete 4c certification, laser girdle code photos, and defects map, in the comments column will also be clearly marked with the production method of cultivated diamonds, the mainstream is currently CVD and HPHT, of course, the quality of CVD will be relatively better and more expensive. At present, the domestic CVD diamond producers, the quality is not bad, in fact, we can count on one hand, such as Henan TEMBO, Ningbo crystal diamond, vân vân. HPHT is more, most concentrated in Henan, such as the TEMBO, Huajing, Zhongnan diamond, vân vân. Because the main force of China’s cultivated diamonds is HPHT diamonds, most of the previous industrial diamonds, but now there are also better quality gem-quality diamonds. The picture shows the 12.75 carat CVD diamond without color change that was cultivated at the Shanghai Fair last year, as well as in-kind, which is the largest loose diamond ever cultivated in the domestic CVD field.
Be on your guard if you encounter colored diamonds. There are tons of lab-grown colored diamonds on the market right now, including BOTH CVD and HPHT. In addition to TEMBO CVD diamonds in China, almost all are color-changing. Why change colors? In fact, it is very simple, the technology of the manufacturer has not reached the level of producing DEF high color grade diamond, HPHT will make the D color diamond look blue to the naked eye, and there will be no fluorescence. The basic principle of color change is through the process of removal of nitrogen-containing HPHT (high pressure inside the diamond, we should know the main reason for the yellow diamond is nitrogen, so remove nitrogen in natural color better, general drilling process to achieve the g h j color is absolutely no problem, but it is important to note that the certificate must show, mainly to view comments. If there is no discoloration, there will be one more sentence: there is no sign of processing after growth. If not, you should be very careful, it is likely to be a color-changing diamond, their value is different, but there are still some merchants that will sell color-changing diamonds without the price of color-changing diamonds, so you should pay attention to. Cuối cùng, all CVD diamonds are essentially 2a and HPHT is not. This is the biggest difference between the two technologies. 2A diamonds have to be purer and have fewer impurities than the other.