Goethite vs. Limonite — What's the Difference?

Goethite (, US also ) is a mineral of the diaspore group, consisting of iron(III) oxide-hydroxide, specifically the "α" polymorph. It is found in soil and other low-temperature environments such as sediment.

Limonite () is an iron ore consisting of a mixture of hydrated iron(III) oxide-hydroxides in varying composition. The generic formula is frequently written as FeO(OH)·nH2O, although this is not entirely accurate as the ratio of oxide to hydroxide can vary quite widely.

A red, yellow, or brown mineral, essentially HFeO2, one of the common constituents of rust.

Any of a group of widely occurring yellowish-brown to black iron oxide minerals, essentially FeO(OH)·(n)H2O, used as a minor ore of iron.

(mineral) An iron oxyhydroxide that is the main constituent of rust.

(mineral) Any of several natural hydrous iron oxides; often a mixture of goethite and hemite with clays and manganese oxide.

An oxide of iron.

Hydrous sesquioxide of iron, an important ore of iron, occurring in stalactitic, mammillary, or earthy forms, of a dark brown color, and yellowish brown powder. It includes bog iron. Also called brown hematite.

A red or yellow or brown mineral; an oxide of iron that is a common constituent of rust

A widely occurring iron oxide ore; a mixture of goethite and hematite and lepidocrocite