sedimentary

Bauxite

Bauxite (mixture of hydrous aluminum oxides: Al(OH)3 & AlO(OH))

AI-generated identification · may be incorrect

Hardness: 1-3 Mohs (soft to the touch), Color: Reddish-brown, yellow, or grey, Luster: Dull to earthy, Structure: Pisolitic (pea-sized round grains) or massive, Specific Gravity: 2.0-2.5

Identified May 12, 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 (soft to the touch), Color: Reddish-brown, yellow, or grey, Luster: Dull to earthy, Structure: Pisolitic (pea-sized round grains) or massive, Specific Gravity: 2.0-2.5

Formation & geological history

Formed through the intense chemical weathering of rocks in hot, humid tropical or subtropical climates, which leaches away silica and results in the accumulation of aluminum oxides.

Uses & applications

Primary ore of aluminum; used in the manufacture of aluminum metal, abrasives, refractories, and chemical industries.

Geological facts

Bauxite is not a single mineral but a mixture of mineral species including gibbsite, boehmite, and diaspore. It was first discovered in 1821 by geologist Pierre Berthier near the village of Les Baux in France.

Field identification & locations

Identify by its 'pisolitic' texture, which looks like a mass of small, rounded pebbles or peas cemented together. Often found in tropical regions like Australia, Guinea, and Brazil.