Epidote

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Epidote — The Deep Green of Alpine Fissures Epidote is a calcium aluminum iron sorosilicate mineral with the formula {Ca₂}{Al₂Fe³⁺}[O|OH|SiO₄|Si₂O₇]. Its distinctive pistachio to forest green color comes from iron (Fe³⁺) in the crystal structure — the more iron, the darker the green. The name comes from the Greek "epidosis" meaning "addition," referring to one side of the crystal being longer than the other. Epidote is a common rock-forming mineral found worldwide, but well-crystallized cabinet specimens are far rarer than the mineral itself. The finest epidote specimens come from Alpine-type fissures in metamorphic rocks — the Austrian Alps (Knappenwand in the Untersulzbachtal is the classic locality), Pakistan's Balochistan province, and Peru's Pampa Blanca district all produce world-class prismatic crystals. Epidote also occurs in contact metamorphic zones, in skarns, and in altered volcanic rocks. Crystals are typically elongated and striated along their length, with a vitreous to resinous luster and a Mohs hardness of 6–7. The pistachio-green color is so characteristic that geologists use the term "epidote green" as a color reference in the field. Browse related green minerals in our green crystals collection , or explore prehnite — another collector-favorite green silicate. For display-quality mineral specimens, see our crystal clusters and Collector's Edition pieces. Take the crystal quiz for a personalized recommendation. Free US shipping on orders over $150. Frequently Asked Questions What is epidote? Epidote is a calcium aluminum iron silicate mineral that belongs to the sorosilicate group. It forms prismatic, elongated crystals with deep pistachio to forest green color caused by iron content. It is a common rock-forming mineral in metamorphic terranes but well-crystallized specimens suitable for collections are relatively uncommon. Where does epidote come from? Epidote is found worldwide, but the finest collector specimens come from the Austrian Alps (esp