SG Heritage Dictionary

Petalite [Noun] Webster's Dictionary 1828

A rare mineral occurring in masses, having a foliated structure; its color milk white or shaded with gray, red or green. The new alkali, lithia, was first discovered in this mineral.

Petalite [Noun] Webster's Dictionary 1913

A rare mineral, occurring crystallized and in cleavable masses, usually white, or nearly so, in color. It is a silicate of aluminia and lithia.