Name: Benitoite
Brand: Alvin B. Stiles

Updated 23h ago

Benitoite

Benitoite, 14 cm, from the Dallas Gem mine (Benitoite Gem mine), New Idria District, San Benito County, California. The mineral benitoite, first found in 1907, was thought to be blue diamond and then blue sapphire until cutters realized that it was too soft to be either. Analysis showed it to be a new species and the mineral was named benitoite after San Benito County. Mining for gem rough resulted in countless gemmy blue crystals being punched out of the matrix, leaving relatively few preserved mineral specimens. Some specimens were purchased by Robert M. Wilke, of Palo Alto, California, who made a deal with Roderick Dallas, owner of the mine, to take all of the neptunite and benitoite specimens that did not have gem potential, sell them to collectors and to split the profit. During this time, the rights to market this gemstone went to G. Eacret of Sheve & Company in San Francisco, who had cut some of the first stones. In 1984 benitoite was named the California State Gemstone. It is probable that the University of Delaware’s specimen was one of these early pieces, as it was traded out of the American Museum of Natural History to Elvis “Buzz” Gray (who leased and owned the mine from 1967 to 2000) in return for specimens that had recently been found. Buzz and his son Mike trimmed the specimen down from a large piece that showed little benitoite and carefully exposed the fragile blue butterfly-like crystals of benitoite using acid to dissolve the enclosing white natrolite. It was later sold to Robert H. Gill, collector and author of “Minerals of the Benitoite Gem Mine,” and went through a couple other hands before it was sold to Alvin B. Stiles who donated it to the University. It has been illustrated in Pemberton’s Minerals of California (1982), and in Wise and Gill (1977, Fig. 9).

Alvin B. Stiles

Product details

Species

Benitoite

Locality

Dallas Gem mine (Benitoite Gem mine), New Idria District, San Benito County, California

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