Spessartine is a nesosilicate, manganese aluminium garnet species, Mn²⁺₃Al₂(SiO₄)₃.^[2][3][4][5] This mineral is sometimes mistakenly referred to as spessartite.^[6]

Spessartine's name is a derivative of Spessart in Bavaria, Germany, the type locality of the mineral.^[3][4] It occurs most often in granite pegmatite^[3][4][5] and allied rock types and in certain low-grade metamorphic phyllites. Sources include Australia, Myanmar, India, Afghanistan, Israel, Madagascar, Namibia, Nigeria, Mozambique, Tanzania and the United States.^[2] 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. In Madagascar, spessartines are exploited either in their bedrock or in alluvium. The orange garnets result from sodium-rich pegmatites. Spessartines are found in bedrock in the highlands in the Sahatany valley. Those in alluvium are generally found in southern Madagascar or in the Maevatanana region.^{[7][8][9][10][11]}

Spessartine forms a solid solution series with the garnet species almandine.^[4][5] 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.^[12] Spessartine, like the other garnets, always occurs as a blend with other species. Gems with high spessartine content tend toward a light orange hue, while almandine prevalence induces red or brownish hues.^[13]

• Spessartine crystal from Pakistan
• Spessartine on smoky quartz: Wushan Spessartine Mine, Tongbei, Fujian Province, China
• Reddish-orange spessartine
• Two "frog-eyes" of 1.8 cm each sit perched atop a matrix