Standard Industry Gemstone Grading
Gemstone Carat Weight
Common Gemstone Treatments
- Emerald - Commonly oiled with colorless oil to improve appearance.
- Ruby - Commonly heated to improve color and appearance.
- Sapphire - Commonly heated to produce intense or light color and/or improve overall color uniformity.
- Tanzanite - Commonly heated to produce blue to violet spectrum colors.
- Aquamarine - Commonly heated to improve color.
- Blue topaz - Commonly irradiated and heated to produce blue color.
- Tourmaline - Commonly irradiated to intensify pink, red and purple color.
- Jade - Commonly impregnated with colorless wax.
- Lapis lazuli - Commonly impregnated with colorless wax or oil.
- Coral - Commonly bleached.
- Pearls - Commonly bleached to improve color and appearance.
- Black onyx – Almost always dyed.