| Orange and Brown Gemstones |
|---|
| Gemstone | Crystal System | Density | Hardness | Refractive index | Treatments |
 Agate |
microcrystalline | 2.66 | 6.5-7.0 | 1.544-1.553 | dying |
 Amber |
amorphous | 1.08 | 2.0-2.5 | 1.54 | heating, oiling, reconstitution |
 Chalcedony |
microcrystalline | 2.66 | 7 | 1.544-1.553 | dying |
 Chrysoberyl |
orthorhombic | 3.72 | 8.5 | 1.746-1.755 | none |
 Coral |
trigonal | 2.65 | 3.5-4.0 | 1.486-1.658 | dying |
 Diamond |
cubic | 3.52 | 10 | 2.417 | radiation, drilling, fracture filling |
 Garnet |
cubic | 3.40 | 5.5-6.5 | 1.700-1.746 | none |
 Jadeite |
microcystalline | 3.34 | 6.5-7.0 | 1.660-1.680 | dying |
 Opal |
amorphous | 2.15 | 5.0-6.5 | 1.450 | fracture filling |
 Spinel |
cubic | 3.60 | 8 | 1.718 | none |