The Collaborative International Dictionary
Spessartite
Spessartite \Spes"sart*ite\, n.[From Spessart, in Germany.] (Min.) A manganesian variety of garnet.
Douglas Harper's Etymology Dictionary
spessartite
manganese garnet, 1853, earlier spessartine (1837), from French spessartine (1832), from Spessart, district in Bavaria where it is found.
Wiktionary
spessartite
n. spessartine