sedimentary

Bauxite

Alumina ore (Mixture of Gibbsite, Boehmite, and Diaspore)

AI-generated identification · may be incorrect

Hardness: 1-3 Mohs; Color: Brown, reddish-brown, white, gray, or yellow; Luster: Dull to earthy; Crystal Structure: Amorphous (mixture of minerals); Specific Gravity: 2.0-2.6

Hardness: 1-3 Mohs
Color: Brown, reddish-brown, white, gray, or yellow
Luster: Dull to earthy

Identified May 26, 2026More sedimentary →

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Physical properties

Hardness: 1-3 Mohs; Color: Brown, reddish-brown, white, gray, or yellow; Luster: Dull to earthy; Crystal Structure: Amorphous (mixture of minerals); Specific Gravity: 2.0-2.6

Formation & geological history

Formed through the intense chemical weathering (lateritization) of rocks such as limestone, basalt, or granite in hot, humid tropical or subtropical climates.

Uses & applications

The primary ore used in the production of aluminum. Also used in abrasives, refractories, and chemicals such as aluminum sulfate.

Geological facts

Bauxite is not a single mineral but a rock essentially composed of hydrated aluminum oxides. It was first discovered in 1821 by geologist Pierre Berthier near the village of Les Baux in France.

Field identification & locations

Identify by its earthy, clay-like appearance, lack of crystalline structure, and often 'oolitic' or 'pisolitic' (pea-like) rounded texture. Commonly found in Australia, Guinea, and Brazil.