Andradite garnet
Andradite garnet is a member of the garnet group, once referred to as "lime garnet" after the word for lime. It is found in skarn deposits and serpentinite, characterized by a wide range of hues from vivid green and yellow to black.
Andradite garnet is prized for its vivid colors and high dispersion.
Basic Information
| English Name | Andradite garnet |
|---|---|
| Japanese Name | 灰鉄柘榴石 (Kaitetsu zakuroishi) |
| Chemical Formula | Ca3Fe23+[SiO4]3 |
| Crystal System | Isometric |
| Hardness | 6.5 |
| Specific Gravity | Approx. 3.84 |
| Transparency | Transparent to translucent |
Characteristics & Varieties
- Demantoid: A vivid green variety colored by Cr.
- Topazolite: A yellow variety.
- Melanite: A black variety.
- Rainbow Garnet: A variety where excess iron forms a thin oxidation layer on specific crystal faces, producing iridescent colors through light interference.
Origin, Synonyms, Treatments & Similar Stones
Representative Origins: Russia, Italy, Mexico, Tenkawa Village in Nara Prefecture.
Synonyms: Siberian chrysolite, Uralian emerald, olivine, diamond.
Treatments: Heat treatment (to remove brown or black tones and enhance color).
Similar Stones: Grossular (distinguished by higher dispersion and stronger iridescent sparkle)
Note: Andradite is singly refractive, has weak magnetism, and exhibits a dazzling iridescent effect due to its high dispersion.