Following are 9 indexes for the evaluation of mineral crystal decoration stone

1. Species: the rarer, the better, the gem mineral is most valuable. “Rare” refers to some peculiar and rare phenomenon as crystalline form, crystal twin and etc.

2. Integrity: the subtle damage would affect its value;

3. Crystal size: the key point is the protrusion of mineral;

4. Bright color: colorful and sound contrast ( it can highlight the decoration stone);

5. Transparency and gloss: the crystal is transparent and gloss. If it is the opaque mineral, it should be with strong gloss.

6. Stability: anti-oxidation and anti-corrosion are available for stone minerals. But because they changed rapidly, cinnabar and realgar were just hot in the market for a short period;

7. The species of mineral paragenesis are rich and coordinate well;

8. Modeling and surrounding rock;

9. Peculiar phenomenon: such as rare crystal twin or combination.