Mineral · Epidote group
Epidote
Ca2(Al2Fe3+)(Si2O7)(SiO4)O(OH)
Epidote is the pistachio-green to black striated monoclinic crystals of Knappenwand (Austria), Prince of Wales Island (Alaska), Capelinha (Brazil) and Pakistan. Knappenwand and Alaskan epidote with quartz are museum classics; Pakistani crystals are abundant and cheap. The yellow-green colour and long, grooved prisms are distinctive.
| Formula | Ca2(Al2Fe3+)(Si2O7)(SiO4)O(OH) |
|---|---|
| IMA status | grandfathered |
| Crystal system | Monoclinic |
| Mohs hardness | 6–7 |
| Group | Epidote group |
| Type locality | None |
| Streak | Greyish white |
| Specific gravity | 3.4 |
| Reference list | IMA List of Minerals (RRUFF) — verify formula and status against the current list |
Elsewhere
Cite this article
Stratum Study. "Epidote" (Mineral). Stratum Study pack 2026.09, as of 2026-09-19. https://stratum.black/study/minerals/epidote. Accessed 2026-09-20.
@misc{stratum-epidote,
title = {Epidote},
author = {{Stratum Study}},
howpublished = {\url{https://stratum.black/study/minerals/epidote}},
year = {2026},
note = {Mineral article, Stratum Study pack 2026.09, as of 2026-09-19; sources: stratum, wikidata, commons. Accessed 2026-09-20.}
} Citations carry the pack version and the article's as-of date so they resolve to the same text later. The facts themselves belong to the sources listed below; cite those for the science.