Spessartine
Spessartine is a variety of garnet, named after the district of Spessart, in northwestern Bavaria, Germany, where the gemstone was first mined. It is found in colours ranging from yellowish-orange to reddish-orange and may also be brownish-red. Reddish-orange spessartine are the most valuable, the deeply saturated colours and a bright vitreous lustre produce very attractive stones. Fine spessartine with good clarity can demand very high prices. The market presence of spessartine has fluctuated over the years as supply has been inconsistent, hence the price has also fluctuated.
Colour change garnet is a mixture of spessartine and pyrope garnets, the colours change from to green or greyish blue in sunlight (daylight) to red in incandescent light (from a filament light bulb). Mandarin spessartine is a yellow-orange stone found in Madagascar and Namibia.
Source locations for spessartine include: Africa (Kenya, Nigeria, Namibia, and Tanzania) Brazil, China, Madagascar (a source of mandarin garnet), Sri Lanka and the USA (California).
Properties of the Gemstone and Additional Information
| Gemstone type: | Spesartine is a member of the garnet group. |
| Crystal System: | Cubic (isometric) commonly occurring as rhombic dodecahedron and icositetrahedal crystals. |
| Chemical Composition: | Mn3Al2(SiO4)3 |
| Colour: | Shades of orange: yellowish-orange to reddish-orange, may also be brownish-red and violet-red. Spessartine is coloured by manganese. |
| Lustre: | Bright vitreous |
| Pleochroism: | None |
| Dispersion: | Low |
| Hardness: | 7 1/4 on the Mohs' scale |
| Toughness: | Good |
| Cleavage: | None |
| Density in gm/cc: | 4.12 to 4.20 |
| Double refraction: | None |
| Refractive index: | 1.790 to1.82 |
Common Treatments
Spessartine is not normally treated.