Muscovite is the most common mica mineral, easily identified by its perfect basal cleavage that allows it to be split into thin, flexible, transparent sheets. It is a primary constituent of many igneous and metamorphic rocks and is frequently found as large 'books' in pegmatites. Collectors look for well-formed pseudohexagonal crystals or large, flawless sheets.
Is this muscovite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch muscovite with a known reference. Muscovite sits at Mohs 2.5-4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to pearly or silky.
- 4Match the color rangeCompare against the expected color range: colorless, yellow, brown, green, white, gray, silver white, brownish white, greenish white.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: foliated, massive, micaceous.
Often confused with
Muscovite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads vitreous to pearly or silky on Muscovite and splendent to submetallic, vitreous, pearly on cleavage on Biotite.
How to tell apart: Luster reads vitreous to pearly or silky on Muscovite and pearly to submetallic on cleavage on Phlogopite.
How to tell apart: Luster reads vitreous to pearly or silky on Muscovite and pearly to vitreous on Lepidolite.
Often found alongside muscovite
Minerals reported to co-occur with muscovite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- KAl₂(AlSi₃O₁₀)(OH)₂
- Mohs hardness
- 2.5-4
- Density
- 2.77-2.88 g/cm³
- Streak
- White
- Luster
- Vitreous to pearly or silky
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
- Crystal habit
- Foliated, massive, micaceous
- Cleavage
- {001} perfect; partings on {110}, {010}
- Rarity
- Common
- Uses
- Industrial, Collector, Electrical insulation
- Host rock
- A common rock-forming mineral, in phyllites, schists, and gneisses; in granites, granite pegmatites, and aplites
Where rockhounds find muscovite
44 mapped spotsClassic worldwide localities
- Mt. Mica, near Paris, Oxford Co., Maine, USA
- Pennsbury, Chester Co., Pennsylvania, USA
- Amelia, Amelia Co., Virginia, USA
- Shelby, Cleveland Co., North Carolina, USA
- Slyudyanka, near Lake Baikal, Siberia, and at Mursinka, Ural Mountains, Russia
- Kammerfors, Kragerö, and Bamble, Norway
U.S. states with muscovite
Each link opens a state-specific list of mapped rockhounding spots that produce muscovite.
Field-hunting tip
Where it forms: A common rock-forming mineral, in phyllites, schists, and gneisses; in granites, granite pegmatites, and aplites. If you start seeing quartz, plagioclase, potassic feldspar in float, you are in the right ground. Typical habit: foliated, massive, micaceous. Train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Connecticut, Maine, North Carolina. Start trip planning there.
More muscovite photos
Common questions
How do you identify muscovite?+
Where is muscovite found?+
Can I find muscovite in the United States?+
What rocks look like muscovite?+
What minerals are found with muscovite?+
What kind of rock does muscovite form in?+
What is muscovite used for?+
Find muscovite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
