Epidote
Epidote is a user that is unusual of Epidote number of minerals that includes Allanite, Clinozoisite, Epidote, Hancockite, Mukhinite, Piedmontite, Tanzanite, Thulite and Zoisite. Epidote is normally therefore dark green it appears nearly black. Smaller gems can be very bright green but. It can be found in many locations through the entire world (including Colorado), but gem quality crystals are somewhat rare. Epidote can be quite a fibrous, nearly opaque mineral that would only yield catseyes or cabachons so faceted gems are rare.
There are lots of locations worldwide were Epidote is found but few produce gem quality crystals. A gem that is few are Corinthia and Salzburg, Austria; Minas Gerais, Brazil; Provence-Alpes-Côte d’Azur & Bourg d’Oisans, Isère, Rhône-Alpes, France; Aosta Valley, Italy; Baltistan & Tormiq, Pakistan; Ticino, Switzerland; Chaffee County, Colorado, United States Of America and Lamoille & Orleans Counties, Vermont, United States Of America.
| Category: | Sorosilicates |
| Formula: | {Ca2}{Al2Fe3+}[O|OH|SiO4|Si2O7] |
| Crystallography: | Monoclinic – Prismatic |
| Crystal Habit: | Crystals prismatic to 35cm. Fibrous, coarse to fine granular, massive |
| Twinning: | On [100], contact, lamellar, common |
| Cleavage: | [001] Perfect, [100] Imperfect |
| Fracture: | Irregular/Uneven |
| Tenacity: | Brittle |
| Hardness (Mohs): | 6.0 – 7.0 |
| Density: | 3.38 – 3.49 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Color: | Pistachio-Green to pale Green, Yellow, Yellowish Green, Greenish Yellow, Greenish Black; |
| Transparency: | Transparent, Opaque |
| Luster: | Vitreous, Pearly |
| Refractive Index: | 1.715 – 1.797 Biaxial ( – ) |
| Birefringence: | 0.019 – 0.046 |
| Dispersion: | 0.019; Strong; r > v |
| Pleochroism: | Strong; X = colorless, pale yellow, pale green; Y = greenish yellow; Z = yellowish green |
