Mineral Species: Cobaltocalcite

Chemical Formula: (Ca,Co)CO3

Chemical Name: Cobalt Calcium Carbonate

Mineral Class: Carbonate

Mineral Notes: Cobaltoan Calcite or Cobaltocalcite is a mineral in which a proportion of the Calcium atoms have been replaced by Cobalt. The amount of Cobalt varies between locations and therefore the mineral forms a solid solution series between Calcite and Sphaerocobaltite. The transition metal gives the mineral its attractive pink colour. As a result the mineral is highly sought after.

Description: A brown matrix on which sits a crust of amorphous Cobaltoan Calcite. The mineral has a very bright violet-pink colour which gradually fades to the side of the specimen where the content of Cobalt declines. The crust shows many botryoid-like undulations and together with a pearly luster makes this a very pretty display specimen.

Location: Tynebottom Mine, Garrigill, Alston, Cumbria, England.