montroseite
/mɒnˈtrəʊˌzʌɪt/Mineralogy
noun
An oxyhydroxide of vanadium and iron, (V,Fe+3)O(OH), occurring as microscopic black crystals of the orthorhombic system.
Origin
1950s. From Montrose, the name of a county in Colorado, where the mineral was first found + -ite.