laumontite

Etymology
Named after the discoverer François Pierre Nicholas Gillet de Laumont (1747–1834) as lomonite, renamed as laumonite in 1809 and as laumontite in 1821.

Noun

 * 1)  A mineral, of a white color and vitreous luster, with the chemical formula CaAl2Si4O12&middot;4H2O. It is a hydrous silicate of alumina and lime. Exposed to the air, it loses water, becomes opaque, and crumbles.