As a qualified gemstone, at least the following three conditions should be met. 1, beautiful: This is the first condition, requiring a bright and pure color
Positive, transparent and shiny, or special optical effects such as color change, discoloration, glare or cat's eye. 2. Durability: It is required to maintain the durability of glamorous and glittering, that is, it must be hard, wear-resistant and have good chemical stability. 3, rare: refers to the scarcity of output is expensive.