sedimentary

Bauxite

Bauxite (Al(OH)3, γ-AlO(OH), and α-AlO(OH))

AI-generated identification · may be incorrect

Hardness: 1-3 Mohs; Color: reddish-brown, white, tan, or grayish; Luster: dull to earthy; Structure: pisolitic (pea-like) or earthy; Cleavage: none; Specific Gravity: 2.0-2.5

Hardness: 1-3 Mohs
Color: reddish-brown, white, tan, or grayish
Luster: dull to earthy

Identified May 3, 2026More sedimentary →

Explore Bauxite in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 1-3 Mohs; Color: reddish-brown, white, tan, or grayish; Luster: dull to earthy; Structure: pisolitic (pea-like) or earthy; Cleavage: none; Specific Gravity: 2.0-2.5

Formation & geological history

Formed as a residual soil in tropical and subtropical regions through the intense chemical weathering (lateralization) of silicate rocks like granite, basalt, or shale. Typically Cenozoic to recent in age.

Uses & applications

Primary ore of aluminum; used in the manufacture of abrasives, cement, chemicals, and refractory materials.

Geological facts

Bauxite is not a mineral in the strict sense but a mixture of hydrous aluminum oxides. It was first discovered in 1821 by Pierre Berthier near the village of Les Baux in France.

Field identification & locations

Identify by its distinctive pisolitic (round, pea-sized) texture and clay-like or earthy appearance. It is commonly found in tropical belts such as Guinea, Australia, Brazil, and Jamaica. Collectors look for well-defined pisolites.