mineral

Epidote

Epidote (formula: Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))

Hardness: 6-7 on Mohs scale. Color: Pistachio green to blackish-green. Luster: Vitreous to pearly. Crystal Structure: Monoclinic, often forming prismatic crystals. Cleavage: Perfect in one direction. Specific Gravity: 3.3 - 3.5.

Hardness: 6-7 on Mohs scale
Color: Pistachio green to blackish-green
Luster: Vitreous to pearly

Identified March 29, 2026More mineral →

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Physical properties

Formation & geological history

Epidote is a common rock-forming mineral formed in low-to-medium grade metamorphic rocks, such as greenschist. It also occurs in igneous rocks through hydrothermal alteration of plagioclase feldspars. Found in a variety of geological ages.

Uses & applications

Primarily of interest to mineral collectors. High-quality transparent crystals are occasionally faceted as gemstones for jewelry. It also serves as an indicator mineral for geologists studying metamorphic facies.

Geological facts

The name comes from the Greek word 'epidosis', meaning 'addition', referring to the crystal's base being longer on one side. It is the namesake of the Epidote group of minerals.

Field identification & locations

Identify in the field by its distinctive 'pistachio' green color and its hardness (it will scratch glass). Commonly found in contact metamorphic zones and hydrothermal veins. Frequent locations include the Alps, Norway, and various sites across the United States.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Epidote

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

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

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Metamorphic Rock

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Epidote

Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)

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