What is "carobbiite"

n. (context mineral English) potassium fluoride, a rare, soft, colourless cubic mineral.

Carobbiite, chemical formula KF ( potassium fluoride), is a rare, soft (Mohs 2 - 2.5), colorless cubic mineral. It is found at Monte Somma, Somma- Vesuvius Complex, Province of Naples, Campania, Italy. It was discovered in 1956 by Italian geologist Guido Carobbi (1900–1983). It has also been reported from Hokkaido, Japan.