nesquehonite
/ˌnɛskwɪˈhəʊnʌɪt/Mineralogy
noun
A hydrated form of magnesium carbonate, MgCO3·3H2O, crystallizing in the monoclinic system and occurring as colourless or white prismatic crystals.
Origin
Late 19th century. From Nesquehon- (in Nesquehoning, the name of a mine in Pennsylvania) + -ite: see quot. 1890.