'Sodalite' definitions:

Definition of 'sodalite'

noun

A vitreous mineral consisting of sodium aluminum silicate and sodium chloride in crystalline form; occurs in igneous rocks

From: GCIDE

Sodalite \So"da*lite\, n. [Soda + -lite: cf. F. sodalithe.] (Min.) A mineral of a white to blue or gray color, occuring commonly in dodecahedrons, also massive. It is a silicate of alumina and soda with some chlorine. [1913 Webster]