Margarite is a brittle mica that forms typically as platy, pearly aggregates in metamorphic environments. Unlike common micas, its sheets are brittle and do not flex or elasticize when bent, a key characteristic for field identification.
Is this margarite?
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 margarite with a known reference. Margarite sits at Mohs 3.5-4.5, 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: pearly on cleavage, vitreous on lateral faces.
- 4Match the color rangeCompare against the expected color range: white, gray, pinkish gray, yellowish gray.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: lamellar, massive, scaly.
Often confused with
Margarite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads pearly on cleavage, vitreous on lateral faces on Margarite and vitreous to pearly or silky on Muscovite.
How to tell apart: Margarite is noticeably harder (Mohs 3.5-4.5 vs. 1).
Often found alongside margarite
Minerals reported to co-occur with margarite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaAl₂(Al₂Si₂)O₁₀(OH)₂
- Mohs hardness
- 3.5-4.5
- Density
- 2.99-3.08 g/cm³
- Colors
- Streak
- White
- Luster
- Pearly on cleavage, vitreous on lateral faces
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Lamellar, massive, scaly
- Cleavage
- {001}, perfect
- Fluorescence
- Sky blue under SW UV; strong sky blue under LW UV
- Rarity
- Uncommon
- Uses
- Collector, Scientific research
- Host rock
- From low- to medium-grade metamorphic rocks, as in emery deposits, chlorite and mica schists, and glaucophane-bearing rocks
Where rockhounds find margarite
Classic worldwide localities
- Chester, Hampden Co., Massachusetts, USA
- Cruger's Point, Peekskill, Putnam Co., New York, USA
- Franklin and Sterling Hill, Ogdensburg, Sussex Co., New Jersey, USA
- Corundum Hill, Chester Co., and Village Green, Delaware Co., Pennsylvania, USA
- Mt. Greiner, in the Zillertal, Tirol, Austria
- Mákares and Naxos Islands, Greece
Field-hunting tip
Where it forms: From low- to medium-grade metamorphic rocks, as in emery deposits, chlorite and mica schists, and glaucophane-bearing rocks. If you start seeing corundum, diaspore, tourmaline in float, you are in the right ground. Typical habit: lamellar, massive, scaly. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify margarite?+
Where is margarite found?+
What rocks look like margarite?+
What minerals are found with margarite?+
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What is margarite used for?+
Find margarite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
