Biotite vs Turquoise
| Property | Biotite | Turquoise |
|---|---|---|
| Formula | K(Mg,Fe)3(AlSi3O10)(OH)2 | CuAl6(PO4)4(OH)8 · 4H2O |
| Crystal System | Monoclinic | Triclinic |
| Mineral Class | 09 Silicates | 08 Phosphates, Arsenates, and Vanadates |
| Mohs Hardness | 2.5-3.0 | 5.0-6.0 |
| Color | Black, dark brown, dark green | Sky blue, blue-green, green |
| Luster | Vitreous | Waxy |
| Streak | White to gray | White to pale green |
| Transparency | Translucent | Translucent |
| Cleavage | Perfect basal {001} | None |
| Fracture | Uneven | Conchoidal |