sedimentary
Bauxite
Aluminium ore (Hydrated aluminium oxides AlOx(OH)3-2x)
Hardness: 1-3 on the Mohs scale, Color: reddish-brown, white, tan, yellow, Luster: dull to earthy, Crystal structure: amorphous to microcrystalline, Specific gravity: 2.0-2.5
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Physical properties
Hardness: 1-3 on the Mohs scale, Color: reddish-brown, white, tan, yellow, Luster: dull to earthy, Crystal structure: amorphous to microcrystalline, Specific gravity: 2.0-2.5
Formation & geological history
Formed by the weathering of aluminum-rich rocks in tropical and subtropical climates, typically through intense leaching of silica and other soluble components over millions of years (Laterite weathering process).
Uses & applications
Primary ore used for the production of aluminum metal via the Bayer and Hall-Héroult processes.
Geological facts
Bauxite is not a distinct mineral, but a rock composed mainly of hydrous aluminum oxides, most commonly gibbsite, boehmite, and diaspore, mixed with iron oxides, silica, and clay minerals.
Field identification & locations
Identified by its pisolitic or pellet-like texture, reddish-brown color, and extreme softness. Found extensively in Australia, Guinea, Brazil, and Jamaica.
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