Image: <a rel="nofollow" class="external text" href="https://www.flickr.com/people/47445767@N05">James St. John</a> (CC BY 2.0)
monocliniccommonSilicates (Phyllosilicates, Mica Group)
Muscovite
KAl₂(AlSi₃O₁₀)(OH)₂
Muscovite typically forms in thin, flexible, transparent to translucent sheets with a clearish-silvery to pale green color and a pearly luster, as seen in the image alongside darker biotite.
Muscovite Physical Properties
Mohs Hardness
2Crystal System
monoclinicLuster
vitreousStreak Color
whiteCleavage
perfect basal (one direction)Fracture
unevenSpecific Gravity
2.76Colors
colorless, white, silver, pale brown, pale greenTransparency
transparent to translucentType Locality
Ruggles Pegmatite Mine, New Hampshire, USAMineral Group
Silicates (Phyllosilicates, Mica Group)Uses
electrical insulator, filler in paints and plastics, decorative material, lubricantAssociated Minerals
biotite, quartz, feldspar, tourmaline, garnetRarity
commonGeological Context
Muscovite is a common rock-forming mineral found in igneous rocks like granite and pegmatites, and in metamorphic rocks such as schists and gneisses, often forming during regional metamorphism.
