Boehmite
Species (IMA name: Böhmite)
Common · AlO(OH)
Aluminium oxide hydroxide, one of the three main minerals of bauxite, first described in 1927 from the bauxites of Les Baux in Provence. It is almost always too fine to see, in pisolites and earthy masses; it also forms late in nepheline pegmatites and syenites. The form of the alumina in a bauxite sets the conditions under which the Bayer process dissolves it.
Identity
- Formula
- AlO(OH)
- Chemical class
- Oxide
- Also known as
- Böhmite
- Ore of
- Aluminum
Crystallography
- Crystal system
- Orthorhombic
- Habits
- Tabular, Nodular, Massive, Earthy
- Fracture
- Uneven
Physical properties
- Mohs hardness
- 3.5
- Density
- 3.03 g/cm³
- Luster
- Vitreous, Pearly
- Colors
- white, brownish gray
- Streak
- white
- Transparency
- Translucent
Geology
- Origins
- Sedimentary, Hydrothermal
- Host rocks
- Granite
- Associated minerals
- Gibbsite, Diaspore, Nepheline, Natrolite, Analcime
- Found in
- Bauxite, Laterite, Lateritic deposit, Pegmatite deposit
- Geography
- France (Les Baux, Provence), Hungary (Baratka), Norway (Langesundsfjord), Italy (Montecchio Maggiore), USA (Georgia, California)
Classification
- Rarity
- Common
- Gem quality
- No
Sources
- M. Pasero and others, IMA Commission on New Minerals, Nomenclature and Classification, The New IMA List of Minerals, updated September 2026. International Mineralogical Association (CNMNC), 2026.
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Böhmite. Mineral Data Publishing, Handbook of Mineralogy, 2001.
- Boehmite. Wikipedia.
- Bauxite. Wikipedia.
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