sedimentary

Bauxite

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

AI-generated identification · may be incorrect

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

Hardness: 1-3 Mohs
Color: Reddish-brown, pink, yellow, or grey
Luster: Dull/earthy

Identified April 7, 2026More sedimentary →

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Physical properties

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

Formation & geological history

Formed by the intense chemical weathering of rocks in hot, humid tropical or subtropical climates. It is the result of the leaching of silica and other soluble materials, leaving behind aluminum oxides. Most deposits are from the Mesozoic or Cenozoic eras.

Uses & applications

Primary ore of aluminum. Used in the production of aluminum metal, refractory materials, chemicals, and abrasives.

Geological facts

Bauxite is not a single mineral but a mixture of hydrous aluminum oxides like gibbsite, boehmite, and diaspore. The red color is typically due to the presence of hematite (iron oxide).

Field identification & locations

Identify by its distinctive 'pisolitic' texture (looking like it is made of small stuck-together pebbles) and its earthy smell when damp. Found globally in belts like Jamaica, Australia, Guinea, and Brazil.