Mineral

Epidote

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

Hardness: 6-7 (Mohs scale); Color: Pistachio-green to yellowish-green or olive-green; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Perfect in one direction; Specific gravity: 3.3 to 3.5.

Hardness: 6-7 (Mohs scale)
Color: Pistachio-green to yellowish-green or olive-green
Luster: Vitreous to pearly

Identified March 24, 2026More mineral →

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Physical properties

Formation & geological history

Formed through regional or contact metamorphism of calcium-rich rocks. It is commonly found in greenschists and as an alteration product of plagioclase feldspar. Geological age varies based on the host formation (Proterozoic to Tertiary).

Uses & applications

Primarily used as a minor semi-precious gemstone for jewelry when transparent, and widely used by mineral collectors for its unique green color. It has limited industrial use besides as a component in construction aggregate when found in large rock masses.

Geological facts

The name 'Epidote' comes from the Greek word 'epidosis,' meaning 'addition,' referring to the characteristic shape of its crystals where one side of the prism is longer than the other. It is the signature mineral of the 'Epidote-Amphibolite' metamorphic facies.

Field identification & locations

Identify in the field by its distinct 'pistachio' green color and relatively high hardness. It is commonly found in Alpine-type veins, skarns, and metamorphic rocks across Norway, Austria, USA (Alaska/California), and Brazil.