Spherocobaltite

Spherocobaltite is a rare mineral composed of cobalt carbonate, with the chemical formula CoCO3. It is a member of the calcite group and is isostructural with calcite itself. Spherocobaltite typically occurs as small, spherical aggregates, often found lining cavities in other minerals or as a secondary mineral in cobalt-rich ore deposits. The name derives from its characteristic spherical habit.

This mineral is known for its distinctive pink to purplish-red color, which is due to the presence of cobalt. It has a Mohs hardness of approximately 4 to 4.5 and a specific gravity of around 4.13. Spherocobaltite is relatively soft and can be scratched by a knife. It is insoluble in water but dissolves readily in acids, producing effervescence and a pink solution.

Spherocobaltite is often found associated with other cobalt minerals such as erythrite (cobalt bloom), skutterudite, and linnaeite. It is a secondary mineral, meaning it forms through the alteration of primary cobalt-bearing minerals, typically in oxidized zones of hydrothermal veins or in sedimentary deposits. Notable occurrences have been reported in regions like the Katanga Province in the Democratic Republic of Congo, and in various locations in Germany, France, and the United States. Due to its rarity and attractive color, spherocobaltite is of interest to mineral collectors.