L1 /
6
CH3041
Biotite
MICAS
Mica
minerals are a common part of clays.
• True micas: 1o silicate
minerals
- Biotite K(Mg,Fe)3AlSi3O10(OH)2 2:1
(shorthand
for K2[Mg4Fe2Al2Si6O20(OH)4]
Muscovite
• Hydrous micas: 2o silicate
minerals,
similar structures to biotite & muscovite but
more water and less K+ in the interlayer.
similar structures to biotite & muscovite but
more water and less K+ in the interlayer.
• Muscovite & Biotite both weather to form
vermiculite ® smectite ® kaolinite.
vermiculite ® smectite ® kaolinite.
- Muscovite
KAl3Si3O10(OH)2 2:1
