ˈsiləməˌnīt noun
( -s )
Etymology: Benjamin Silliman died 1864 American chemist and geologist + English -ite
: a brown, grayish, or pale green mineral Al 2 SiO 5 that consists of an aluminum silicate in orthorhombic crystals often occurring in fibrous or columnar forms and that is polymorphous with cyanite and andalusite — called also fibrolite ; see sillimanite group