sedimentary
Bauxite
Bauxite (Al(OH)3, AlO(OH))
Hardness: 1-3 Mohs; Color: reddish-brown, white, gray, or yellow; Luster: dull to earthy; Structure: Pisolitic (pea-shaped) or massive; Fracture: uneven; Opaque.
- Hardness
- 1-3 Mohs
- Color
- reddish-brown, white, gray, or yellow
- Luster
- dull to earthy
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Physical properties
Hardness: 1-3 Mohs; Color: reddish-brown, white, gray, or yellow; Luster: dull to earthy; Structure: Pisolitic (pea-shaped) or massive; Fracture: uneven; Opaque.
Formation & geological history
Formed as a residual mineral after the weathering of silicate rocks in tropical or subtropical climates, causing the leaching of silica and leaves behind enriched aluminum oxides. Primarily from the Cenozoic era.
Uses & applications
The primary ore for aluminum production. Used in refractories, abrasives, chemicals, and cement industries.
Geological facts
Bauxite is not a mineral in the strict sense but a mixture of hydrous aluminum oxides like gibbsite, boehmite, and diaspore. It is named after the village Les Baux in southern France where it was first discovered in 1821.
Field identification & locations
Identify by its distinctive 'pisolitic' (clumpy, pea-like) texture and lightweight feel compared to iron ores. Found in weathered tropical regions like Australia, Guinea, Brazil, and Jamaica.
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