Adularia
Pronunciation : Ad`u*la"ri*a
Part of Speech : n.
Etymology : [From Adula, a mountain peak in Switzerland, where fine specimens are found.] (Min.)
Definition : Defn: A transparent or translucent variety of common feldspar, or orthoclase, which often shows pearly opalescent reflections; -- called by lapidaries moonstone.
Source : Webster's Unabridged Dictionary, 1913