Böhmite is a major constituent of bauxite ore and typically forms in low-temperature hydrothermal or sedimentary environments. It is rarely found in well-formed crystals, most often appearing as white, chalky masses, pisolites, or thin, pearly crusts within aluminum-rich sedimentary rocks.
Is this böhmite?
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 böhmite with a known reference. Böhmite sits at Mohs 3-3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Böhmite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Böhmite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: white, gray, yellowish, greenish, brownish.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: pisolitic, massive, or as fibrous aggregates.
Often confused with
Böhmite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Diaspore is the harder of the two (Mohs 6.5-7 vs. 3-3.5); luster reads pearly on Böhmite and vitreous on Diaspore.
How to tell apart: Luster reads pearly on Böhmite and vitreous on Gibbsite.
How to tell apart: Luster reads pearly on Böhmite and dull on Kaolinite.
Often found alongside böhmite
Minerals reported to co-occur with böhmite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- γ-AlO(OH)
- Mohs hardness
- 3-3.5
- Density
- 3.0-3.1 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Pisolitic, Massive, Or as Fibrous Aggregates
- Cleavage
- Perfect On {010}
- Rarity
- Common
- Uses
- Industrial, Collector
- Host rock
- Bauxite Deposits
- Typical price
- $10-50 for thumbnail specimens
Where rockhounds find böhmite
Classic worldwide localities
- France
- Hungary
- Greece
- USA
- Jamaica
Field-hunting tip
Look in bauxite deposits country, the host setting where böhmite typically forms. If you start seeing gibbsite, diaspore, hematite in float, you are in the right ground. Field specimens usually show a pisolitic, massive, or as fibrous aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify böhmite?+
Where is böhmite found?+
How much is böhmite worth?+
What rocks look like böhmite?+
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Find böhmite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
