What is "spessartine"

n. (context mineralogy English) A neosilicate of manganese and aluminium having the garnet structure, with the chemical formula manganese₃²⁺aluminum₂(siliconoxygen₄)₃.

Spessartine, sometimes mistakenly referred to as spessartite, is a nesosilicate, manganese aluminium garnet species, MnAl(SiO).

The name is a derivative of Spessart in Bavaria, Germany, the type locality of the mineral. It occurs most often in granite pegmatite and allied rock types and in certain low-grade metamorphic phyllites. Sources include Australia, Myanmar, India, Afghanistan, Israel, Madagascar, Tanzania and the United States. 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.

Spessartine forms a solid solution series with the garnet species almandine. 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. 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.

The mineral spessartite should not be confused with a type of igneous rock (a lamprophyre) called spessartite.