metamorphic
Epidote
Epidote (Ca2(Al,Fe)3(SiO4)3(OH))
Hardness: 6-7 (Mohs); Color: Pistachio green, yellowish-green, or brownish-green; Luster: Vitreous to resinous; Crystal structure: Monoclinic; Cleavage: Perfect in one direction; Specific gravity: 3.3-3.6
- Hardness
- 6-7 (Mohs)
- Color
- Pistachio green, yellowish-green, or brownish-green
- Luster
- Vitreous to resinous
Identified More metamorphic →
Explore Epidote in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 (Mohs); Color: Pistachio green, yellowish-green, or brownish-green; Luster: Vitreous to resinous; 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 or hydrothermal alteration of igneous rocks. It is a common constituent of greenschist facies rocks.
Uses & applications
Used primarily as low-cost gemstones (cabochons), for mineral collecting, and occasionally as an indicator mineral for copper gold porphyry deposits in geological surveying.
Geological facts
The name comes from the Greek word 'epidosis', meaning addition, referring to the unequal sides of the crystal base. Epidote is famous for its distinct 'pistachio' green color, which is rarely matched by other minerals.
Field identification & locations
Identify in the field by its characteristic yellowish-green color and hardness. It is commonly found in association with quartz, chlorite, and feldspar in metamorphic terrains such as the Alps or the Appalachian Mountains.
More like this
