elpidite
noun
el·pi·dite
ˈelpəˌdīt
plural -s
: a mineral Na2ZrSi6O15.3H2O consisting of a hydrated sodium zirconium silicate
Word History
Etymology
Swedish elpidit, from Greek elpid-, elpis hope + Swedish -it -ite; from the expectation of finding other minerals in the same locality