epidote

Borrowed from French épidote.

epidote (countable and uncountable, plural epidotes)

1. (mineralogy) Any of a class of mixed calcium iron aluminium sorosilicates found in metamorphic rocks.
   • 1915, George Curtis Martin, Bertrand Leroy Johnson, Ulysses Sherman Grant, Bulletin 587: Geology and Mineral Resources of Kenai Peninsula, Alaska, United States Geological Survey, page 23,

     A little higher is an outcrop of epidote schist with quartz, carbonate, and magnetite.

   • 1990, Andrew P. Barth, Chapter 3: Mid-crustal emplacement of Mesozoic plutons, San Gabriel Mountains, California, and implications for the geologic history of the San Gabriel terrane, J. Lawford Anderson (editor), The Nature and Origin of Cordilleran Magmatism, Memoir 174: The Nature and Origin of Cordilleran Magmatism, The Geological Society of America, page 36,

     Available compositional data for magmatic epidotes (Naney, 1983; Zen and Hammarstrom, 1984; Barth, unpublished data) suggest no significant solid solution beyond the epidote-clinozoisite binary.

   • 2004, Bruce Cairncross, Field Guide to Rocks and Minerals of Southern Africa‎, page 96:

     Epidote is found in greenstone belts and many metamorphic rocks such as gneiss and schist, and is hence fairly widespread.

• “Epidote” in David Barthelmy, Webmineral Mineralogy Database, 1997–.
• “epidote”, in Mindat.org‎, Hudson Institute of Mineralogy, accessed 29 August 2016.

• opetide