Epidote

Physical Properties

Hardness: 6-7 (Mohs scale), Color: Pistachio-green, yellow-green, or brownish-green, Luster: Vitreous to pearly, Crystal structure: Monoclinic, Cleavage: One perfect direction, Specific gravity: 3.3-3.6

Formation & Geological History

Forms during low-to-medium grade regional metamorphism of calcium-rich rocks. It is also found in contact metamorphic zones and as an alteration product of plagioclase feldspar.

Uses & Applications

Used primarily as a collector's mineral and a semi-precious gemstone. Sometimes used as an indicator mineral in mineral exploration for copper deposits.

Geological Facts

The name comes from the Greek word 'epidosis', meaning 'addition', referring to the way one side of the prism is longer than the other at the base of the crystal.

Field Identification & Locations

Identify by its unique 'pistachio' green color and its association with other metamorphic minerals like quartz or actinolite. Common in alpine veins and regional metamorphic terrains.

Identified on: 4/25/2026

Mode: Standard