sedimentary
Bauxite
Bauxite (Al2O3·2H2O mixed with iron oxides)
AI-generated identification · may be incorrectHardness: 1-3 on Mohs scale; Color: Reddish-brown, pismire, gray, or yellow; Luster: Dull to earthy; Structure: Pisolitic (pea-sized round grains) or massive; Non-crystalline mixture; Specific gravity: 2.0-2.5
- Hardness
- 1-3 on Mohs scale
- Color
- Reddish-brown, pismire, gray, or yellow
- Luster
- Dull to earthy
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Physical properties
Hardness: 1-3 on Mohs scale; Color: Reddish-brown, pismire, gray, or yellow; Luster: Dull to earthy; Structure: Pisolitic (pea-sized round grains) or massive; Non-crystalline mixture; Specific gravity: 2.0-2.5
Formation & geological history
Formed through the intense chemical weathering (laterization) of aluminum-rich rocks like granite or basalt in hot, humid tropical or subtropical climates.
Uses & applications
The primary ore of aluminum. Used in the production of aluminum metal, abrasives, refractories, chemicals, and cements.
Geological facts
Bauxite is not technically a mineral but a rock composed of aluminum hydroxide minerals like gibbsite, boehmite, and diaspore. It was first discovered in Les Baux, France, in 1821.
Field identification & locations
Identify by its 'pea-like' (pisolitic) appearance and clay-like feel. Commonly found in tropical regions like Australia, Guinea, Brazil, and Jamaica. Collectors look for well-defined pisoliths.
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