A widely occurring iron oxide ore

• A mixture of goethite and hematite and lepidocrocite

Wiktionary Word definitions in Wiktionary
n. (context mineralogy English) any of several natural hydrous iron oxides; often a mixture of goethite and hemite with clays and manganese oxide

WordNet Word definitions in WordNet
n. a widely occurring iron oxide ore; a mixture of goethite and hematite and lepidocrocite

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Limonite \Li"mon*ite\ (l[imac]"m[o^]n*[imac]t), n. [Gr. leimw`n any moist grassy place, a meadow: cf. F. limonite, G. limonit.] (Min.) Hydrous sesquioxide of iron, an important ore of iron, occurring in stalactitic, mammillary, or earthy forms, of a dark ...

Wikipedia Word definitions in Wikipedia
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)·nHO, although this is not entirely accurate as the ratio of oxide to hydroxide can vary quite ...