There is controversy on whether cobaltocalcite is a mineral on its own or if it is not. It can be described either as calcite mineral containing cobalt or as spherocobaltite containing calcium. It surely is a calcium and cobalt carbonate and, as it happens with spherocobaltite, it is pink, vitreous and it always grows incrusted on a matrix.
The crystal on the image, however, is somewhat special. Although incrusted, it has managed to grow stout. It is common for calcite to grow in a rhombohedral shape; yet it is not to be almost tetrahedral. In addition, it is rare to find a well-defined shape inside a tumult of irregularity. Crystals of cobaltocalcite seem to grow as they please, creating erratic forms empowered with the built up confusion of their shining glassy contours. They end up looking as if they were to have a viscid touch. Misleadingly, nearly deceitfully, they do not; and as with everything in life, the hardest part is to find an uncrooked one. Luckily enough, it is never impossible.
Author: Sergi Batlle