mineral
Epidote
Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
Hardness: 6-7 Mohs; Color: Pistachio-green, yellow-green, or brownish-green; Luster: Vitreous to pearly; Crystal Structure: Monoclinic; Cleavage: Perfect in one direction; Specific Gravity: 3.3-3.6
- Hardness
- 6-7 Mohs
- Color
- Pistachio-green, yellow-green, or brownish-green
- Luster
- Vitreous to pearly
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Physical properties
Hardness: 6-7 Mohs; Color: Pistachio-green, yellow-green, or brownish-green; Luster: Vitreous to pearly; Crystal Structure: Monoclinic; Cleavage: Perfect in one direction; Specific Gravity: 3.3-3.6
Formation & geological history
Forms through regional metamorphism of calcium-rich igneous rocks or hydrothermal alteration. Commonly found in schists, gneisses, and skarns.
Uses & applications
Primarily a collector's mineral; sometimes used as a minor gemstone (Pistacite) or for decorative beads and carvings.
Geological facts
Epidote is named from the Greek word 'epidosis' meaning 'addition' because one side of the ideal prism is longer than the others. It is a key indicator mineral in low-grade metamorphism.
Field identification & locations
Identify in the field by its characteristic 'pistachio green' color and high hardness. Common in mountainous regions with metamorphic history like the Alps or Blue Ridge Mountains.
More like this
Other mineral specimens
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Sandstone with Mineral Veining or Crust
Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)
sedimentary
Schist
Schist
Metamorphic
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic