Laterite (iron-rich nodule, possibly Bauxite as a subtype)

Hardness: Varies (often 1-3 for individual minerals, but rock can be quite resistant when dry); Color: Reddish-brown, brown, sometimes yellowish; Luster: Earthy to dull; Crystal structure: Amorphous to microcrystalline, often nodular or concretionary; Cleavage: None; Specific Gravity: Varies, typically 2.5-3.5

Formed by intense and prolonged weathering of underlying rocks (e.g., granite, basalt, shale) in tropical and subtropical regions. High rainfall leaches soluble components, leaving behind insoluble iron, aluminum, and titanium oxides and hydroxides. The nodular form indicates concretionary growth within the soil profile. The geological age is typically Cenozoic, but can vary depending on the specific weathering event.

Laterite, especially iron-rich varieties, can be used as a source of iron ore. Aluminous laterite (bauxite) is the primary ore for aluminum. It is also used as a road-building material, a construction aggregate, and as a natural pigment (ochre).

Lateritic soils are widespread in tropical regions and are often infertile for agriculture due to nutrient leaching and fixation. The term "laterite" comes from the Latin word "later," meaning brick, due to its ability to harden when exposed to air and be cut into brick-like blocks for construction. The formation of laterite is a key process in the global cycling of iron and aluminum.

In the field, laterite is identified by its reddish-brown color, earthy texture, and often nodular or pisolitic (pea-sized spheres) structure, especially in tropical and subtropical climates. It feels relatively heavy. It can be found capping plateaus or as a thick soil horizon in areas with high rainfall and distinct dry seasons. Tips for collectors include looking for highly weathered landscapes and road cuts in tropical regions. The small size of the specimen in the image suggests it could be a small nodule or a fragment from a larger laterite deposit.