Epidote
The name epidote is derived from the Greek word "epidosis" (increase), while its Japanese name, "Ryokurenseki" (green curtain stone), reflects the way its crystals often aggregate in parallel. This name actually refers to a group of ten minerals, with slight variations in chemical composition resulting in a variety of colors and properties.
Beautiful green epidote
Basic Information
| English Name | Epidote |
|---|---|
| Japanese Name | Ryokurenseki |
| Chemical Formula | Ca2Fe3+Al2[OH|SiO4|Si2O7] |
| System | Monoclinic |
| Hardness | 6–7 |
| Specific Gravity | Approx. 3.4 |
| Transparency | Transparent to translucent |
Characteristics & Variations
- Pistacite: A bright green variety.
- Delphinite: A yellowish-green variety from France.
- Arendalite: A dull green stone from Norway.
- Thulite-related/Tawmawite: A chromium-bearing epidote that exhibits an alexandrite-like color-change effect.
Origins, Aliases, Treatments, & Similar Stones
Major Origins: France, Norway, Myanmar, Takeishi Village (Nagano Prefecture).
Alias: Brazilian Tourmaline (referring to green epidote).
Treatments: Some are dyed; it is important to distinguish between natural and artificially colored specimens.
Similar Stones: Diopside, Thulite (deep black-green varieties are very similar to epidote).
Note: The rarest colors of epidote are vivid greens; it exhibits strong pleochroism, meaning its hue changes depending on the direction of observation.