Carobbiite, chemical formula KF (

potassium fluoride Potassium fluoride is the chemical compound with the formula KF. After hydrogen fluoride, KF is the primary source of the fluoride ion for applications in manufacturing and in chemistry. It is an alkali halide and occurs naturally as the rare ...

), is a rare, soft (Mohs 2 - 2.5), colourless cubic

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ( ...

. It is found at

Monte Somma Mount Somma ( it, Monte Somma) is a mountain located in the Province of Naples, in the Campania region of southern Italy. Mount Somma is an integral part of the Somma–Vesuvius volcanic complex. It is high. Geography Mount Somma is the rem ...

, Somma-

Vesuvius Mount Vesuvius ( ; it, Vesuvio ; nap, 'O Vesuvio , also or ; la, Vesuvius , also , or ) is a somma- stratovolcano located on the Gulf of Naples in Campania, Italy, about east of Naples and a short distance from the shore. It is one of ...

Complex,

Province of Naples The Province of Naples ( it, Provincia di Napoli; nap, Pruvincia 'e Nàpule) was a province in the Campania region of southern Italy. In 2014/2015, the reform of local authorities (Law 142/1990 and Law 56/2014), replaced the Province of Naples ...

Campania Campania (, also , , , ) is an administrative Regions of Italy, region of Italy; most of it is in the south-western portion of the Italian peninsula (with the Tyrrhenian Sea to its west), but it also includes the small Phlegraean Islands and the i ...

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...

. It was discovered in 1956 by Italian geologist Guido Carobbi (1900–1983). It has also been reported from

Hokkaido is Japan's second largest island and comprises the largest and northernmost prefecture, making up its own region. The Tsugaru Strait separates Hokkaidō from Honshu; the two islands are connected by the undersea railway Seikan Tunnel. The la ...

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

.http://www.mindat.org/min-908.html Mindat

References

Potassium minerals Fluorine minerals Cubic minerals Minerals in space group 225 Rocksalt group {{Halide-mineral-stub