Silicates: Muscovite

Composition: K₂Al₄Si₆Al₂O₂₀(OH,F)₄

Crystal system: Monoclinic; lamellar masses or small flakes

5.16.1
cleavable muscovite

Properties:

• Vitreous lustre
• Colorless to pale green or brown
• White streak
• Knife scratches very easily; fingernail barely scratches cleavage faces (Mohs Hardness 2.5-4)
• Average density
• Single perfect cleavage
• Cleaves rather than fractures
• Not ferromagnetic
• Does not react with hydrochloric acid (HCl)

Occurrence:

Muscovite occurs in low grade metamorphic rocks, some granites, pegmatite dikes, hydrothermal vein and replacement ore deposits and as a detrital mineral in immature sandstones.

5.16.2 cleavable muscovite	5.16.3 finegrained chromium muscovite (fuchsite)

Muscovite is a significant industrial mineral that is used in the manufacture of paints, paper, cosmetics, insulators and many other materials.

5.16.4
finegrained chromium muscovite
(fuchsite)