mineral

Epidote

Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))

Hardness: 6-7 Mohs; Color: Pistachio green to yellowish-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 to yellowish-green
Luster: Vitreous to pearly

Identified June 25, 2026More mineral →

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Physical properties

Hardness: 6-7 Mohs; Color: Pistachio green to yellowish-green; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Perfect in one direction; Specific gravity: 3.3-3.6

Formation & geological history

Formed through low-to-medium grade regional metamorphism of igneous and sedimentary rocks, or through hydrothermal alteration of calcium-rich minerals. Often found in schists, gneisses, and skarns.

Uses & applications

Primarily used as a minor gemstone for jewelry when transparent, and highly valued as a collector's specimen. It serves as an indicator mineral for metamorphic grade in geological studies.

Geological facts

The name 'Epidote' comes from the Greek word 'epidosis', meaning 'addition', referring to the unequal sides of the crystal base. It is the most common member of the epidote group.

Field identification & locations

Identify by its distinctive 'pistachio' green color and hardness. Can be found globally, with notable deposits in the Alps, Norway, and the United States (Alaska/California). Look for green veins in metamorphic outcrops.