Brucite is a magnesium hydroxide mineral known for its distinct pearly luster and flexible, sectile nature. It typically forms as foliated masses or tabular crystals in hydrothermal veins and altered serpentinites, making it a key indicator of low-temperature metamorphic conditions.
Is this brucite?
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 brucite with a known reference. Brucite sits at Mohs 2.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Brucite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Brucite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: white, pale green, blue, gray, honey yellow.
- 5Look at form & habitCrystal system: trigonal. Typical habit: tabular crystals, foliated masses, fibrous aggregates.
Often confused with
Brucite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Brucite is noticeably harder (Mohs 2.5 vs. 1).
How to tell apart: Luster reads pearly on Brucite and vitreous on Gypsum.
How to tell apart: Luster reads pearly on Brucite and greasy on Serpentine.
Often found alongside brucite
Minerals reported to co-occur with brucite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mg(OH)₂
- Mohs hardness
- 2.5
- Density
- 2.39 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Tabular Crystals, Foliated Masses, Fibrous Aggregates
- Cleavage
- Perfect Basal
- Rarity
- Common
- Uses
- Collector, Industrial
- Host rock
- Metamorphosed Limestones and Serpentinized Ultramafic Rocks
- Typical price
- $5-40 thumbnail, $20-150 cabinet specimen
Where rockhounds find brucite
7 mapped spotsClassic worldwide localities
- Pennsylvania, USA
- Quebec, Canada
- Ural Mountains, Russia
- Skye, Scotland
Field-hunting tip
Look in metamorphosed limestones and serpentinized ultramafic rocks country — that is the host setting where brucite typically forms. If you start seeing serpentine, dolomite, magnesite in float, you are in the right ground. Field specimens usually show a tabular crystals, foliated masses, fibrous aggregates habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Maryland, Pennsylvania, New York — start trip planning there.
Common questions
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Find brucite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
