mineral

Epidote

{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)

Hardness: 6-7 on Mohs scale; Color: Pistachio green to dark green; Luster: Vitreous to resinous; Crystal structure: Monoclinic; Cleavage: Perfect in one direction; Specific gravity: 3.3 to 3.5.

Hardness: 6-7 on Mohs scale
Color: Pistachio green to dark green
Luster: Vitreous to resinous

Identified June 5, 2026More mineral →

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Physical properties

Hardness: 6-7 on Mohs scale; Color: Pistachio green to dark green; Luster: Vitreous to resinous; Crystal structure: Monoclinic; Cleavage: Perfect in one direction; Specific gravity: 3.3 to 3.5.

Formation & geological history

Formed through regional or contact metamorphism of calcium-rich rocks like basalt, gabbro, or limestone. It often occurs in hydrothermal veins and vugs in igneous and metamorphic rocks.

Uses & applications

Used primarily as low-cost gemstones (cabochons) and by collectors; occasionally used in industrial applications for high-pressure research or as indicator minerals in geological prospecting.

Geological facts

Epidote is well-known for its distinctive 'pistachio green' color. In high-quality transparent crystals, it can exhibit strong pleochroism, showing different colors when viewed from different angles.

Field identification & locations

Identify in the field by its unique yellowish-green color, hardness (it can scratch glass), and elongated prismatic crystal form. It is commonly found in Alpine regions, Norway, Brazil, and the USA (Alaska and California).