Spessartine, sometimes mistakenly referred to as spessartite,[5] is a nesosilicate, manganese aluminium garnet species, Mn2+3Al2(SiO4)3.[1][2][3][4] The mineral spessartine should not be confused with a type of igneous rock (a lamprophyre) called spessartite.
Spessartine's name is a derivative of Spessart in Bavaria, Germany, the type locality of the mineral.[2][3] It occurs most often in granite pegmatite[2][3][4] 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.[1] 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.[6][7][8][9][10]
Spessartine forms a solid solution series with the garnet species almandine.[3][4] 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.[11] 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.[12]
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