Spessartine
| Spessartine | |
|---|---|
 Spessartine from China |
|
| General | |
| Category | Nesosilicate |
| Chemical formula | Mn(II)3Al2(SiO4)3 |
| Strunz classification | 09.AD.25 |
| Identification | |
| Molar mass | 495.03 g |
| Color | yellow through red |
| Crystal habit | massive to crystalline |
| Crystal system | Isometric - Hexoctahedral |
| Fracture | sub Conchoidal |
| Tenacity | brittle |
| Mohs scale hardness | 6.5 - 7.5 |
| Luster | vitreous |
| Streak | white |
| Diaphaneity | transparent to translucent |
| Specific gravity | 4.15 (+.05, -.03)[1] |
| Optical properties | Isotropic, often anomalous double refractive |
| Refractive index | 1.810 (+.004, -.020) |
| Birefringence | none |
| Dispersion | weak |
| Absorption spectra | bands at 410, 420, 430nm (or merging to form cutoff below 430nm; also bands at 460, 480, 520nm. Possible weak bands at 504, or 573nm [1] |
| References | [2][3][4] |
Spessartine previously named spessartite, is a nesosilicate, manganese aluminium garnet species, Mn(II)3Al2(SiO4)3.[1][2][3][4]
The name is a derivative of Spessart in Bavaria, Germany, the type locality of the mineral.[2][3] It occurs most often in granite pegmatite[2][3][4] and allied rock types and in certain low grade metamorphic phyllites. Sources include Australia, Myanmar, India, Afghanistan, Israel, Madagascar, Tanzania and the United States.[1] Spessartine of an orange-yellow has been called Mandarin garnet and is found in Madagascar. . Violet-red spessartines are found in rhyolites in Colorado and Maine.
Spessartine forms a solid solution series with the garnet species almandine.[3][4] Well formed crystals from this series, varying in color from very dark-red to bright yellow-orange were found in Latinka, Rhodope Mountains, Kardzhali Province, Bulgaria.[5]
[edit] References
- ^ a b c d Gemological Institute of America, GIA Gem Reference Guide 1995, ISBN 0-87311-019-6
- ^ a b c d Webmineral Spessartine page
- ^ a b c d e Mindat Spessartine page
- ^ a b c d Handbook of Mineralogy Spessartine page
- ^ "Spessartine from Latinka, Bulgaria:". http://www.mindat.org/locentry-216291.html.
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