stewartite
noun
stew·art·ite
ˈst(y)üə(r)ˌtīt
plural -s
: a mineral consisting of a hydrous phosphate of manganese that is brownish yellow in color, is usually in minute crystals and tufts of fibers, and is found with hureaulite in several pegmatites
Word History
Etymology
Stewart mine, Pala, California, where it was originally found + English -ite