Silicate of manganese and aluminium, belonging to the garnet family. It is named after the Spessart region of Bavaria (West Germany). although only minor deposits are found there.
Crystal system Cubic.
Appearance Spessartine has the typical crystal form olgarnets, usually occurring as isolated, well formed, rhombic dodecahedral crystals. The color is orange-pink, orange-red, or brownish yellow. It may be semiopaque or transparent. Transparent crystals are highly lustrous. lt has no cleavage. The transparent specimens are used as gems.
Physical properties lt has a hardness of 6.5-7.5. The density of gem-quality stones varies from 4.12 to 4.20 g/cm3. The refractive index can vary from about 1.79 to 1.81.
Genesis Spessartine occurs in low-grade metamorphic: rocks, but is uncommon.
Occurrence lt is mainly found in the United States (Virginia and California), Mexico, and Madagascar, but Ellen in West Germany and Italy (Piedmont and Val d’Aosta).