'Laumontite' definitions:

Definition of 'Laumontite'

From: GCIDE

Laumontite \Lau"mont*ite\, n. [From Dr. Laumont, the discoverer.] (Min.) A mineral, of a white color and vitreous luster. It is a hydrous silicate of alumina and lime. Exposed to the air, it loses water, becomes opaque, and crumbles. [Written also laumonite.] [1913 Webster]