Exceptinoal blue fluorite on quartz. La Viesca Mine, Huergo, La Collada mining area, Siero, Asturias, Spain. photo Heritage Auctions

Fluorite is one of the minerals everybody loves and can afford. The fact that it is widely available and generally inexpensive sometimes obscures another fact: it can also occur in forms both rare and highly desirable, especially to connoisseurs. All of the factors that define a superlative specimen are present in this exceptional Spanish blue Fluorite: color, size, aesthetics of composition and matrix, freedom from damage, attractive luster, and relative rank against other known examples.

A light and even, sky-blue tint, characteristic of La Viesca Fluorites is the first thing that greets the eye when viewing it for the first time. On closer inspection, some subtle features become apparent: the color isn't quite sky-blue; it has a turquoise component, and the last few millimeters of the exterior show a faint, violet tinge that is anything but obvious. Three enormous cubes up to 4 inches (10 cm) across dominate the snow-white matrix of stubby and lustrous Quartz crystals. The La Viesca Mine and indeed the entire La Collada district are justly famous for the beauty of the Fluorites found there, but the absolute size and perfection of this example puts in a class of its own.

Others think so too - it was included in the "European Classics" display at the 2011 Munich Show - presented as "The finest Spanish Fluorite ever found". It was the first time this specimen had ever been placed on public display and it caught a lot of people by surprise. It had been found in 2006 and for a while, occupied a prominent spot in the collection of the mine owners' friend who had helped collect it. From his collection it ended up crossing the Atlantic and went into the collection of Gene Meieran: Intel Fellow and a serious collector of fine minerals. A photo of it on display in its Munich case gives a sense of its scale - this important European specimen measures an impressive 17 x 9 x 6 inches high (43 x 24 x 15 cm), and is in excellent condition. Estimate: $300,000 - $350,000.

Provenance: Ex Gene Meieran collection.

Heritage Auctions. 2012 May 20 Natural History Signature Auction- New York