The name comes from the Latin "later", meaning brick. It is applied to any red-brown or yellowish residual mantle in tropical or subtropical regions. Laterites are high in the hydrous iron and aluminum oxides and low in silica. Silica is more readily leached under tropical climates than under any other climatic zone.

A laterite must contain about 50% iron in the form of hydrous iron oxide or an equal amount of aluminum in the form of hydrous aluminum oxide in order to qualify as an ore deposit. These ore deposits are known as lateritic iron ore, and bauxite, respectively.

Chemical Composition of a Basic Igneous Rock (Dunite) and its Residual Regolith (Laterite).

Constituent	Fresh Rock (%)	Weathered Regolith
SiO2	33.9	1.3
Al2O3	1.6	8.2
Fe2O3	8.6	76.8
FeO	7.4	---
CaO	0.5	Trace
MgO	36.7	Trace
H2O	10.6	12.9
Other	0.2	0.3
	_____	_____
	99.5	99.5

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