iron oxides
A third important type of soil is laterite . Laterite forms in tropical areas. Temperatures are warm and rain falls every day Figure below . So much rain falls that chemical weathering is intense. All soluble minerals are washed from the soil. Plant nutrients get carried away. There is practically no humus. Laterite soils are often red in color from the iron oxides. If laterites are exposed to the Sun, they bake as hard as a brick.