The evaluation criteria of diamond quality are called 4C, which are: weight (carat), color (clarity) and cut. These four aspects should be looked at together. Just because a diamond is good doesn't mean it is good enough.

In terms of weight, 1ct = 0.2g = 100 integral, and (on the same premise as other 3C), the heavier it is, the more expensive it is.

Color, D color is the best (100), followed by E, F, G, H, I, J, K, L, M, N, (N is not white).

GIA includes: IF, FL, VVS 1, VVS2, VS 1, VS2, SI 1, SI2, p.

In China, it is divided into LC, VVS, VS, SI and P.

Cutting; GIA is divided into EX, VVS, VS, g.

Domestic: Very good, not bad, just so-so.

K is used to indicate the fineness of gold, 1K=4. 166%, so the gold content of 18K gold is: 4. 166%* 18=75%.

Everyone calls it 18K gold: 750 gold,

Diamond certificate: Gemological Institute of America (GIA); (Currently the most authoritative)

HRD diamond grade certificate, issued by Belgian Diamond High Council (there are also many in China).

IGI diamond grade certificate issued by the International Gemological Association.

EGL diamond grade certificate issued by European Gemological Institute.

NGTC mosaic diamond grading certificate is issued by the National Jewelry and Jade Quality Supervision and Inspection Center.