Mineralpedia Details for Fresnoite
Named for the type locality at the Esquire No. 7 claim in Fresno County in California, USA. Fresnoite is a rare mineral that can be found in additional localities in the United States, as well as in Canada, Germany, and Russia. As its type locality it occurs “disseminated in gneissic metamorphic rocks composed mainly of sanbornite and quartz.” Fresnoite will fluoresce pale yellow under short wave ultraviolet light.
Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/fresnoite.pdf
Fresnoite from Victor claim, Clear Creek area, San Benito Co., California, United States
Bright yellow, translucent, crude crystals to 2mm.
Fresnoite from Junnila claim, San Benito Co., California, United States
1cm Fresnoite crystal.
Fresnoite from Esquire #7 claim, Big Creek, Fresno Co., California, United States
- Special Info
- Type Locality
Bright to light yellow crystal grains to 1mm and less strung out in "veinlets" and disseminations associated with faint blue Benitoite crystal grains less than 0.75mm. Both minerals are fluorescent. The Fresnoite is yellow FL, while the Benitoite is bright blue. The matrix ia a metamorphic barium rich rock of Sanbornite and sulfides. The photo shows the Fresmoite at the red arrows and the Benitoite at the yellow arrows.