Apatite vs Corundum
| Property | Apatite | Corundum |
|---|---|---|
| Formula | Ca5(PO4)3(F,Cl,OH) | Al2O3 |
| Crystal System | Hexagonal | Trigonal |
| Mineral Class | 08 Phosphates, Arsenates, and Vanadates | 04 Oxides and Hydroxides |
| Mohs Hardness | 5.0 | 9.0 |
| Color | Green, blue, yellow, violet, colorless | Red (ruby), blue (sapphire), various colors |
| Luster | Vitreous | Adamantine |
| Streak | White | Colorless |
| Transparency | Transparent | Transparent |
| Cleavage | Poor {0001} | None |
| Fracture | Conchoidal to uneven | Conchoidal to uneven |