Mineralpedia Details for Epidote

Named for the Greek words epiprosthetos, meaning “additionally,” and dido, meaning “to give,” I reference to the additional increase of two of the crystal sides as compared to the third. Epidote is a common mineral found in thousands of localities worldwide with a few notable occurrences that include in France, Norway, Italy, Austria, the United States, Mexico, Namibia, and Pakistan. Epidote occurs in facies of regionally metamorphosed rocks, contaminated felsic igneous rocks, contact zones of igneous and calcareous sedimentary rocks, and as an alteration product of plagioclase via saussuritization.

Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/epidote.pdf

Formula

Ca₂Fe³⁺Al₂(Si₂O₇)(SiO₄)O(OH) 

Crystal System

Monoclinic 

Crystal Habit

Prismatic, Fibrous, Massive 

Cleavage

Perfect, None, None 

Luster

Vitreous (Glassy) 

Color

yellowish green, brownish green, black, yellow, gray 

Streak

grayish white 

Class

Monoclinic - Prismatic 

Fracture

Regular 

Hardness

7 

WebMineral

View Epidote 

Mindat

View Epidote 

Pinkish to carmine red crystal grains of this Manganese rich variety of Epidote. Though Withamite does not contain enough Mn+3 within the structure to be compositionally Piemontite, it is often called "Piemontite" because of the red coloring.

Deep red prismatic Epidote variety Piemontite as ~1cm compact veins and encrustations with lustrous crystals lying flat on pinkish matrix. Epidote variety Piemontite, colored red by an enrichment of Mn, is not to be mistaken for the mineral Piemontite, which is a member of the Epidote group.

Special Info

Chris van Laer collection

Pistachio green divergent group of slender prismatic crystals.

Dark green, nicley terminated, well-formed crystal.