Aragonite

Pink cobalt-bearing aragonite specimen from the Richelsdorf District, Wildeck, Hesse, Germany. The specimen consists of massive to crystalline aragonite showing an attractive pink coloration caused by minor cobalt substitution, a well-known feature of aragonite from this historic mining region.

Aragonite is a calcium carbonate mineral and a polymorph of calcite, crystallizing in the orthorhombic system. It commonly forms in low-temperature environments, including hydrothermal veins, sedimentary settings, and oxidation zones of ore deposits. In the Richelsdorf District, cobalt-bearing aragonite developed in association with polymetallic mineralization.

The Richelsdorf mining district is a classic German locality known for copper and cobalt mineralization, and pink aragonite from this area is a well-established collector material, valued for its color and historical provenance rather than crystal perfection.

Cobalt-bearing aragonite is considered uncommon, especially in well-preserved matrix specimens. The mineral is stable under normal collection conditions, though aragonite may alter to calcite over geological timescales.