| Diamond |
Transparent |
Carbon |
| Ruby |
Pink to Red |
Corundum (Aluminium oxide Al2O3) |
| Emerald |
Green |
Beryl (Be3Al2(SiO3)6) |
| Sapphire |
Blue |
Corundum (α-Al2O3) |
| Amethyst |
Violet |
Quartz (Silicon dioxide SiO2) |
| Opal |
Variety of colours |
Hydrated silica (SiO2·nH2O) |
| Turquoise |
Blue to greenish |
Hydrated copper and aluminium phosphate [CuAl6(PO4)4(OH)8·4H2O] |
| Topaz |
Variety of colours |
Aluminum silicate containing fluorine (Al2(F,OH)2SiO4) |
| Lapis Lazuli |
Deep blue |
Metamorphic rock with mineral lazurite as its chief constituent |
| Aquamarine |
Pale greenish blue or bluish green |
Beryl (Be3Al2(SiO3)6) |
| Morganite |
Pink to orange-pink |
Beryl (Be3Al2(SiO3)6) |
| Onyx |
Bands of black and white |
Silicon dioxide (SiO2)) |
