Benitoite is a rare blue silicate mineral, found in hydrothermally altered serpentinite. Benitoite fluoresces under short wave ultraviolet light, appearing light blue in color. Dr. Louderback, who conducted the discovery examination of this mineral, named it Benitoite, “as it occurs near the head waters of the San Benito River in San Benito County,” California.[3][4]
Benitoite's rarity makes it a minor ore for barium or titanium at best. Rather, benitoite's main uses are as collector's specimens, especially in specimens which show off this mineral's unique crystals, or specimens in which benitoite occurs with its commonly associated minerals. Benitoite's hardness also makes it suitable for use as a gemstone, though the general lack of usable material has limited this use.
Associated minerals and locations
Benitoite typically occurs with an unusual set of minerals, along with minerals that make up its host rock. Frequently associated minerals include:
Benitoite is a rare mineral, found in very few locations, most prominently in southern San Benito County, California, but also in Japan and Arkansas. In the San Benito occurrence it is found in natrolite veins within glaucophaneschist within a serpentinite body. In Japan it occurs in a magnesio-riebeckite-quartz-phlogopite-albite dike cutting a serpentinite body.[5] Benitoite is typically found with some combination of natrolite, joaquinite, and neptunite on a greenish-grey serpentinite base. Finally, benitoite's fluorescence is used for identification purposes.
Trivia
Benitoite is the official state gem of California.[6]
^ Louderback, George Davis. Bentiote, A New California Gen Mineral. Bulletin of The Department of Geology, Vol. 5, No. 9. University of California Publications. July, 1907
^ http://www.mineralsocal.org/scfm/newsletters/2002%20march.htm Friends of Mineralogy review of benitoite
^ http://rruff.geo.arizona.edu/doclib/hom/benitoite.pdf Handbook of Mineralogy
^ http://www.consrv.ca.gov/cgs/geologic_resources/mineral_resource_mapping/ Mineral Resources California Geologic Survey. Accessed December 31, 2005
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