Laterites are mineral deposits rich in iron and aluminum and are formed through tropical weathering of rock. In Geologica, laterite soil and ores are in the form of clay. In the tropics (any biome with sufficiently high temperature and rainfall), there are two types of laterite deposits: limonite and bauxite. Swamps also host limonite. Geologica divides limonite ore into two types: yellow and brown. There is no functional difference between the two, yet.
Beneath some laterite deposits, one will encounter veins of serpentinite that are enriched for garnierite, an ore of nickel.