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 27, 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 regional or contact metamorphism of calcium-rich rocks like basalt, gabbro, or limestone. Often found in hydrothermal veins and skarn deposits.

Uses & applications

Primarily used as a minor gemstone or for mineral collecting specimens. Occasionally used as an indicator mineral for copper and gold mining exploration.

Geological facts

The name comes from the Greek word 'epidosis', meaning 'addition', in reference to one side of the prism being longer than the others. It is a common constituent of the rock Unakite.

Field identification & locations

Identified in the field by its distinct 'pistachio' green color. Common in metamorphic terrains and often associated with quartz, feldspar, and chlorite.