Anhydrite (classic material) (ex David Burgess Collection)

Item Description

Chemically, Anhydrite is anhydrous calcium sulfate (CaSO4) and is closely related to Gypsum, which is HYDROUS calcium sulfate CaSO4-2H20. The Naica Mine is world-famous for producing the largest, most spectacular crystals of Gypsum or "Selenite" in the world (up to 12 m {39 ft} in length, 4 m {13 ft} in diameter and 55 tons in weight), but the superb old classic blue Anhydrites from this locality are some of the best crystals of that species as well. Not only is it difficult to find good quality euhedral crystals of Anhydrite from anywhere in the world, but to find BLUE crystals like this is exceptionally rare. This piece is a beautiful cabinet-sized display specimen of this well-known material featuring excellent, broad, thick, lustrous, pale grey-blue colored heavily striated crystals of Anhydrite free of matrix. Virtually every crystal is terminated (I can see only a few contacts), and the fact that they have grown in a "spray"-like formation makes the piece very enticing. Very aesthetic, superb form and wonderful crystallization. Valued at $950. Specimen weight is 279.20 grams. From the worldwide collection of David Burgess (1951-2016) with a document / invoice from the Mineral of the Month Club. David was a prolific species collector from Newington, Connecticut, and the namesake for the extremely rare cobalt arsenate species Burgessite, which he discovered.