Really Rare Minerals

Every now and then, when leafing through reference texts like the Encyclopedia of Minerals, one comes across a particularly unusual occurrence of a rare mineral. These are both reasonably interesting, showing the diverse environments in which minerals can form; and amusing, when you consider the plight of the species collector, who aims to possess a specimen of all known minerals.

ABHURITE is found as blisterlike growths on tin ingots from a shipwreck in an arm of the Red Sea known as Sharm Abhur, 30 km north of Jiddah, Saudi Arabia.

ACETAMIDE is found in waste piles in a coal mine in the L'vov-Volynskii basin, former USSR, only in ammonia-rich areas, and only in periods of dry weather.

AMMONIOBORITE occurs admixed with larderellite and sassolite in the boric acid lagoon at Lardarello, Tuscany, Italy.

ANTARCTICITE was found crystallizing from the brine of Don Juan Pond, Victoria Land, Antarctica.

ARCANITE was found as yellow crystals in a pine railroad tie in Tunnel #1 of the Santa Ana Tin Mine, Orange County, California.

BARRINGERITE occurs along the contacts between schreibersite and troilite in the Ollague pallasite meteorite.

MITSCHERLICHITE was found as stalactites on the floor of the crater of Mt.Vesuvius, Italy.

MOOLOOITE was found in an outcrop 12 km east of Mooloo Downs station homestead, Western Australia, where it occurs as a result of the interaction of bat guano with weathering copper sulfides.

NEWBERYITE, along with struvite and magnesite, "was found filling interglobular spaces in the ivory of a mammoth tusk. The tusk was found at a depth of some 5 meters in the surface bed of frozen muck on Quartz Creek, a tributary of the Indian River [Newfoundland]" - Traill, GSC Paper 80-18, p.255

ROMARCHITE was found as a thin crust on tin pannikins lost from the overturned canoe of a voyager between 1801 and 1821, found 15 feet below the surface of the water at Boundary Falls, Winnipeg River, Ontario.

Anybody else have any good ones?