Search Mineralpedia – A Mineral Photo Database and Identification Guide
Named for the Greek words epiprosthetos, meaning “additionally,” and dido, meaning “to give,” I reference to the additional increase of two of the crystal sides as compared to the third. Epidote is a common mineral found in thousands of localities worldwide with a few notable occurrences that include in France, Norway, Italy, Austria, the United States, Mexico, Namibia, and Pakistan. Epidote occurs in facies of regionally metamorphosed rocks, contaminated felsic igneous rocks, contact zones of igneous and calcareous sedimentary rocks, and as an alteration product of plagioclase via saussuritization.
Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/epidote.pdf
Named after the Greek word epistoli, meaning letter, presumably meaning a written letter on paper, in reference to the minerals flat and rectangular crystal habit and white color. Epistolite can be found at a number of localities in only three countries which include, Greenland in the Ilimaussau intrustion, from the Lovozero Massif in Russia, and from Mont Saint-Hilaire and Saint-Amable in Canada. Epistolite can be found in alkalic pegmatites, albitites, sodalite, and hydrothermal veins.
Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/epistolite.pdf