Limonite (Goethite) pseudomorph. Pyrite/Marcasite XL size

Limonite (Goethite) pseudomorph. Pyrite/Marcasite, XL size

Sahara, North Africa.

A single piece. Size approx 58mm x 65mm x 61mm. Weight about 530g.

In this large, heavy and unique piece, limonite or goethite (also an iron hydroxy mineral) has almost completely replaced the original crystal structure of pyrite or marcasite. This rare, exceptionally beautiful specimen is unevenly round in shape. The color is a beautiful reddish dark brown with a dull golden glow of pyrite.

Limonite is a general name for hydrous iron oxide precipitates. They are also called lake and marsh ores, depending on the place of precipitation. Before the large-scale start of mining, limonite was the most important raw material for iron production in Finland. Folk names for limonite are hölmä, malavi, rautamaa, malvi and rauamult. As an actual mineral species, they mostly contain goethite when the substance is crystalline. Pseudomorphosis is a geological phenomenon in which the original mineral of a mineral grain is replaced by another, but its original shape remains.