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 — that is 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?+
What minerals are found with böhmite?+
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What is böhmite used for?+
Find böhmite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
