sedimentary
Bauxite
Aluminum ore (mixture of gibbsite Al(OH)3, boehmite γ-AlO(OH), and diaspore α-AlO(OH))
Hardness: 1-3 on Mohs scale; Color: Reddish-brown, white, tan, yellow; Luster: Dull to earthy; Structure: Pisolitic (pea-sized rounds) or massive; Specific Gravity: 2.0-2.5.
- Hardness
- 1-3 on Mohs scale
- Color
- Reddish-brown, white, tan, yellow
- Luster
- Dull to earthy
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Physical properties
Hardness: 1-3 on Mohs scale; Color: Reddish-brown, white, tan, yellow; Luster: Dull to earthy; Structure: Pisolitic (pea-sized rounds) or massive; Specific Gravity: 2.0-2.5.
Formation & geological history
Formed by the intense chemical weathering of rocks (like granite or basalt) in hot, humid tropical or subtropical climates. It is a residual soil layer where silica has been leached away, leaving concentrated aluminum oxides.
Uses & applications
The primary ore of aluminum used worldwide. Utilized in the metallurgical industry, abrasive manufacturing, chemical production, and as a refractory material in furnace linings.
Geological facts
Named after the village Les Baux in southern France where it was first discovered in 1821. It is technically a rock composed of several aluminum-rich minerals rather than a single mineral species.
Field identification & locations
Identify by its earthy, dull reddish appearance and often 'pisolitic' texture (looking like small spheres cemented together). Commonly found in Australia, Guinea, Brazil, and Jamaica.
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