Rock Identifier
Laterite (Laterite (Iron/Aluminum-rich oxide)) — sedimentary
sedimentary

Laterite

Laterite (Iron/Aluminum-rich oxide)

Hardness: 2.0-3.5 on Mohs scale (soft when wet, hardens when dry); Color: Rusty red, brown, or yellow due to iron oxides; Luster: Dull to earthy; Structure: Pitted, porous, or vesicular texture; Specific Gravity: 2.5-3.5.

Hardness
2
Color
Rusty red, brown, or yellow due to iron oxides
Luster
Dull to earthy
Identified More sedimentary

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Physical properties

Hardness: 2.0-3.5 on Mohs scale (soft when wet, hardens when dry); Color: Rusty red, brown, or yellow due to iron oxides; Luster: Dull to earthy; Structure: Pitted, porous, or vesicular texture; Specific Gravity: 2.5-3.5.

Formation & geological history

Formed through intense and long-lasting weathering of underlying parent rock in tropical/subtropical climates. High rainfall leaches away silica, leaving behind insoluble iron and aluminum oxides. Geological age varies from Quaternary to ancient Tertiary periods.

Uses & applications

Major source of aluminum (Bauxite is a type of laterite). Historically and currently used as a building block (masonry) in tropical regions such as India and Southeast Asia. Used in road construction and as a substrate in aquariums.

Geological facts

The word 'laterite' comes from the Latin 'later', meaning brick. Many famous ancient structures, such as Angkor Wat in Cambodia and numerous South Indian temples, were built primarily using laterite blocks.

Field identification & locations

Identified in the field by its distinct reddish-orange color, porous 'sponge-like' appearance, and the fact it can often be cut with a spade when freshly dug but becomes rock-hard after exposure to air. Commonly found in India, Brazil, Australia, and Africa.