Clay Pit, Neusafenau, Hartberg, Styria, Austria

FeO(OH)·nH₂O

Colour: light brown, brown, yellowish-brown
Lustre: earthy
Habitus: fine-grained aggregates or coatings. It can occur as pseudomorph after Fe minerals (e.g., pyrite).
Hardness: 4 - 5½
Density: 2.7 - 4.3 g/cm³
Origin and geological occurrence: limonite is not a mineral. On the contrary it is a rock mainly formed by a mixture of microcrystalline to nanocrystalline Fe oxides and hydroxides (e.g., hematite, goethite, lepidocrocite).

 www.mindat.org

Samples:

1.8 Limonite Massive earthy limonite.  #oxides