Almandine - is a mineral, ferruginous and the most common variety of garnet. Has a reddish color. High-quality jewelry almandines can be confused with ruby or noble spinel. So, the main upper stone of the large imperial crown is the Russian almandine from the Kitelsky manifestation, Karelia.
You can see almandine stone for sale and buy it in the Minerals of Russia online store.
General | |
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Category | Nesosilicate |
Formula (repeating unit) |
Fe2+3Al2Si3O12 |
IMA symbol | Alm |
Strunz classification | 9.AD.25 |
Crystal system | Cubic |
Crystal class | Hexoctahedral (m3m) H-M symbol: (4/m 3 2/m) |
Space group | Ia3d |
Identification | |
Color | reddish orange to red, slightly purplish red to reddish purple and usually dark in tone |
Cleavage | none |
Fracture | conchoidal |
Mohs scale hardness | 7 - 7.5 |
Luster | greasy to vitreous |
Streak | white |
Specific gravity | 4.05 (+.25, -.12) |
Polish luster | vitreous to subadamantine |
Optical properties | Single refractive, and often anomalous double refractive |
Refractive index | 1.790 (+/- .030) |
Birefringence | none |
Pleochroism | none |
Dispersion | .024 |
Ultraviolet fluorescence | inert |
Absorption spectra | usually at 504, 520, and 573nm, may also have faint lines at 423, 460, 610 and 680-690nm |