metamorphic
Epidote
Epidote Group (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))
Hardness: 6-7 (Mohs scale); 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 scale)
- Color
- Pistachio-green to yellowish-green
- Luster
- Vitreous to pearly
Identified More metamorphic →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 (Mohs scale); 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
Forms primarily in low to medium-grade metamorphic environments, such as greenschist facies. It is also found in contact metamorphism of limestones and produced during hydrothermal alteration of pyroxenes and feldspars.
Uses & applications
Primarily valued by mineral collectors for its unique color. It has limited use as a minor gemstone when transparent; sometimes used as a decorative stone in construction when part of unakite (epidotized granite).
Geological facts
The name comes from the Greek 'epidosis' meaning 'increase,' referring to its crystal base being longer on one side. It is the signature mineral of the greenschist metamorphic facies.
Field identification & locations
Identify in the field by its distinctive 'pistachio green' color and prismatic crystal habit. It is commonly found in areas of altered igneous rock or metamorphic belts like the Alps or the Appalachian Mountains.
More like this
