Mineralpedia Details for Elpasolite
Named for the type locality in St. Peters Dome in the Cheyenne district of El Paso (Elpaso) County in Colorado, USA. Elpasolite is a rare mineral that can be found in additional USA localities as well as in Italy, Greenland, Ukraine, Russia, and the Democratic Republic of the Congo. Elpasoite occurs as a replacement for fluorine minerals in quartz-microcline pegmatites and in quartz veins associated with hydrothermal antimony deposits in silicon rich limestone.
Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/elpasolite.pdf
Elpasolite from Le Cetine mine, Rosia, Siena, Tuscany, Italy
Analcime looking, clear crystals to about 0.5mm in and on vuggy matrix associated with Gypsum.