sedimentary

Bauxite

Bauxite (mainly Al(OH)3, AlO(OH))

Hardness: 1-3 Mohs (often soft/earthy); Color: Reddish-brown, white, tan, yellow; Luster: Dull, earthy; Structure: Pisolitic (pea-like or rounded grains); Specific Gravity: 2.0-2.55

Hardness: 1-3 Mohs (often soft/earthy)
Color: Reddish-brown, white, tan, yellow
Luster: Dull, earthy

Identified April 7, 2026More sedimentary →

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Physical properties

Hardness: 1-3 Mohs (often soft/earthy); Color: Reddish-brown, white, tan, yellow; Luster: Dull, earthy; Structure: Pisolitic (pea-like or rounded grains); Specific Gravity: 2.0-2.55

Formation & geological history

Formed by the intense chemical weathering of rocks in hot, humid tropical or subtropical climates, resulting in the leaching of silica and accumulation of aluminum oxides. Typically found in lateritic soils.

Uses & applications

Primary ore of aluminum worldwide. Used in the production of alumina (Al2O3), cement, chemicals, refractories, and abrasives.

Geological facts

Bauxite is not a single mineral but a mixture of hydrous aluminum oxides like gibbsite, boehmite, and diaspore. It is named after the village of Les Baux in southern France where it was first discovered.

Field identification & locations

Identify in the field by its distinctive pisolitic (round, pea-shaped) texture and earthy, clay-like appearance. It is much lighter than similar-looking iron ores. Commonly found in Guinea, Australia, Brazil, and Vietnam.