Laterite

Laterite is a red-colored clay rich soil found in the tropics and subtropics. It is typically an infertile soil. Bricks made out of dried or baked laterite make a good building material. Most of the temples of the Khmer empire in South-East Asia are built with this material and have survived for over 1000 years.

The name laterite derives from the Latin word later, meaning brick, referring to the soil's red brick-like color. Laterite needs the high temperatures and rainfall of the tropics to form. The water washes out the sodium, potassium, calcium, magnesium, and other metals, and enriches the soil with aluminium phyllosilicates, aluminium oxides, iron(III) oxides and hydroxides. The iron in particular provides the typical red color. Laterites particularly rich in the aluminium oxides called bauxite are mined as aluminium ore.

Laterites that form on areas underlain by mafic to ultramafic igneous rocks often result in the secondary concentration of nickel in the form of nickel-bearing limonite and the silicate mineral garnierite. These nickel bearing laterites form an important orebody class and are a major source of nickel.