sedimentary
Bauxite
Bauxite (Mixture of Al(OH)3, AlO(OH), and Fe2O3)
Hardness: 1-3 (Mohs scale), Color: Reddish-brown, pink, yellow, or grey. Luster: Dull to earthy. Structure: Pisolitic (pea-like) or massive. Specific Gravity: 2.0-2.5.
- Color
- Reddish-brown, pink, yellow, or grey
- Luster
- Dull to earthy
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Physical properties
Hardness: 1-3 (Mohs scale), Color: Reddish-brown, pink, yellow, or grey. Luster: Dull to earthy. Structure: Pisolitic (pea-like) or massive. Specific Gravity: 2.0-2.5.
Formation & geological history
Formed through the intense chemical weathering (laterization) of aluminum-rich rocks in tropical or subtropical climates. It is the world's main source of aluminum.
Uses & applications
Primary ore for aluminum production. Used in the manufacture of abrasives, cement, chemicals, and refractory materials.
Geological facts
Bauxite is named after the village of Les Baux in southern France, where it was first discovered in 1821. It is technically a rock composed of various aluminum hydroxide minerals rather than a single mineral.
Field identification & locations
Identify by its dull, clay-like appearance and characteristic 'pea-shaped' round grains (pisolites). Found in abundance in Guinea, Australia, Brazil, and Jamaica. Collectors look for high iron content for deeper red colors.
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