noun
also lau·mon·ite or lo·mon·ite lōˈmän(t.)ˌīt
( -s )
Etymology: laumontite, laumonite alteration of lomonite, irregular from F. P. N. G. de Laumont died 1834 French mineralogist + English -ite
: a white monoclinic mineral CaAl 2 Si 4 O 12 .4H 2 O consisting of a hydrous calcium and aluminum silicate and having a vitreous luster that upon exposure to the air loses water, becomes opaque, and crumbles