Biotite

Properties

Formula K(Mg,Fe)3AlSi3O10(OH,F)2
Abbreviation Bt
Classification Mica
Members Tetraferriannite, Fluorophlogopite, Eastonite, Annite, Tetraferriphlogopite, Oxyphlogopite, Fluorotetraferriphlogopite, Fluorannite, Phlogopite, Siderophyllite
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