Amazonite vs Biotite
| Property | Amazonite | Biotite |
|---|---|---|
| Formula | KAlSi3O8 | K(Mg,Fe)3(AlSi3O10)(OH)2 |
| Crystal System | Triclinic | Monoclinic |
| Mineral Class | 09 Silicates | 09 Silicates |
| Mohs Hardness | 6.0-6.5 | 2.5-3.0 |
| Color | Green, blue-green | Black, dark brown, dark green |
| Luster | Vitreous | Vitreous |
| Streak | White | White to gray |
| Transparency | Translucent | Translucent |
| Cleavage | Perfect {001}, good {010} | Perfect basal {001} |
| Fracture | Conchoidal to uneven | Uneven |