Spessartine is an uncommon garnet, mostly found in granites and pegmatites. It ranges in color from red-brown to yellow-brown. Its orange occurrence is a gemstone known as mandarin garnet.
Spessartine is one of the aluminum garnets, along with almandine and pyrope forming the "pyralspite" group. Its ideal composition is Mn2+3Al2(SiO4)3. Almandine and pyrope have iron (Fe) and magnesium (Mg), respectively, instead of the manganese (Mn).