Bauxite

Physical Properties

Hardness: 1-3 Mohs; Color: reddish-brown, white, tan; Luster: earthy/dull; Structure: Pisolitic (pea-sized round grains) or massive; Specific Gravity: 2.0-2.5.

Formation & Geological History

Formed through the chemical weathering (laterization) of aluminum-rich rocks in tropical or subtropical climates. It is the primary ore for aluminum and often dates from the Mesozoic to Cenozoic eras.

Uses & Applications

Primary source of aluminum; used in metallurgy, chemicals, abrasives, and refractory materials.

Geological Facts

Bauxite is not a single mineral but a rock composed mainly of aluminum oxide minerals like gibbsite, boehmite, and diaspore. The red color is usually due to iron oxide impurities.

Field Identification & Locations

Identify by its distinctive 'pisolitic' circular grain pattern and earthy texture. It is lighter than it looks and lacks a crystalline sparkle. Commonly found in Guinea, Australia, Brazil, and Jamaica.

Identified on: 4/13/2026

Mode: Standard