sedimentary
Bauxite
Bauxite (Al2O3·2H2O mixed with iron oxides)
Hardness: 1-3 on Mohs scale; Color: Reddish-brown, pismire, gray, or yellow; Luster: Dull to earthy; Structure: Pisolitic (pea-sized round grains) or massive; Non-crystalline mixture; Specific gravity: 2.0-2.5
- Hardness
- 1-3 on Mohs scale
- Color
- Reddish-brown, pismire, gray, or yellow
- Luster
- Dull to earthy
Identified More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 1-3 on Mohs scale; Color: Reddish-brown, pismire, gray, or yellow; Luster: Dull to earthy; Structure: Pisolitic (pea-sized round grains) or massive; Non-crystalline mixture; Specific gravity: 2.0-2.5
Formation & geological history
Formed through the intense chemical weathering (laterization) of aluminum-rich rocks like granite or basalt in hot, humid tropical or subtropical climates.
Uses & applications
The primary ore of aluminum. Used in the production of aluminum metal, abrasives, refractories, chemicals, and cements.
Geological facts
Bauxite is not technically a mineral but a rock composed of aluminum hydroxide minerals like gibbsite, boehmite, and diaspore. It was first discovered in Les Baux, France, in 1821.
Field identification & locations
Identify by its 'pea-like' (pisolitic) appearance and clay-like feel. Commonly found in tropical regions like Australia, Guinea, Brazil, and Jamaica. Collectors look for well-defined pisoliths.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone Grain
Clastic Sedimentary Rock Grain (SiO2 dominated)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Sandstone
Arenite
sedimentary