Biotite
Properties
| Formula | K(Mg,Fe)3AlSi3O10(OH,F)2 |
| Abbreviation | Bt |
| Classification | Mica |
| Members | Annite, Eastonite, Tetraferriphlogopite, Fluorannite, Fluorotetraferriphlogopite, Fluorophlogopite, Phlogopite, Oxyphlogopite, Siderophyllite, Tetraferriannite |
| IMA Status | Approved group |
| Search other databases | webmineral.com, mindat.org, rruf.info, mineralienatlas.de, Handbook of Mineralogy, American Mineralogist Crystal Structure Database |
| Crystal symmetry | Monoclinic, Point group 2/m, Space group C2/m (#12) |
| Tags | Hydroxide , Subgroup, Aluminosilicate |
Composition
| Element | Wt% |
|---|---|
| H | 0.41 |
| K | 9.02 |
| Mg | 14.02 |
| Fe | 6.44 |
| Al | 6.22 |
| Si | 19.44 |
| O | 43.36 |
| F | 1.1 |
| Total: | 100.01 |