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]