Goethite Pseudomorph. Marcasite

Goethite Pseudomorph. Marcasite

Sahara, North Africa.

Single piece. Size approx. 38mm x 28mm x 30mm. Weight approx. 68g.

In this spectacular and rare specimen, goethite has almost completely replaced the original crystal structure of pyrite or marcasite. This exceptionally beautiful specimen is irregularly round in shape. The color is a beautiful reddish dark brown with a faint golden sheen from pyrite or marcasite.

Limonite is a general name for hydrous iron oxide deposits. They are also called lake ore and bog ore depending on the place of deposition. Before large-scale mining began, limonite was the most important raw material for iron production in Finland. The common names for limonite are hölmä, malavi, rautamaa, malvi and rautamulta. The actual mineral species most often found in them is goethite when the substance is crystalline. Pseudomorphosis is a geological phenomenon in which the original mineral of a mineral grain changes to another but its original shape is preserved.