First of all, I declare that I graduated from jewelry major and worked as a diamond wholesaler for 5 years. Diamonds have no brand, only the quality of diamonds themselves.

Diamonds are classified by 4C. 4C is weight, clarity, color and cut.

The purity of finished products is divided into (good or bad) vvs vs si p.

The color of the finished product is divided into (good to bad) D-EF-GHI-JK-Lm-N.

Cutting is divided into (domestic certificate does not cut) EXVG GD F.

There is fluorescence, coffee, milk and green. These things are hidden.