metamorphic
Muscovite schist
Mica schist, chiefly muscovite mica (KAl₂(AlSi₃O₁₀)(OH)₂) with quartz and feldspar
AI-generated identification · may be incorrectTypically silver-gray, strongly foliated, and sparkly with platy mica; muscovite hardness is 2–2.5, quartz about 7. It has a micaceous luster, schistosity, and splits readily along aligned mica layers; the specimen may also contain rusty iron-oxide staining.
Identified More metamorphic →
Explore Muscovite schist in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Typically silver-gray, strongly foliated, and sparkly with platy mica; muscovite hardness is 2–2.5, quartz about 7. It has a micaceous luster, schistosity, and splits readily along aligned mica layers; the specimen may also contain rusty iron-oxide staining.
Formation & geological history
Formed when shale or other clay-rich sediment was subjected to regional metamorphism, commonly during mountain building. Its age depends on locality, but such rocks are often Paleozoic to Precambrian.
Uses & applications
Used locally as decorative stone, landscaping rock, fill, and occasionally roofing or wall material; attractive specimens are collected but are generally not gemstone-grade.
Geological facts
The glitter comes from light reflecting off millions of aligned muscovite flakes. Its pronounced foliation records directed pressure and elevated temperature during metamorphism.
Field identification & locations
Identify it by silvery sparkle, wavy layered texture, and flakes that peel or separate along foliation; quartz-rich bands and rusty weathering support the identification. Common in metamorphic mountain belts worldwide, including the Appalachians, New England, Scandinavia, and the Alps.
More like this
