Vivianite
Pronunciation : Viv"i*an*ite
Part of Speech : n.
Etymology : [So called by Werner after the English mineralogist F. G. Vivian.] (Min.)
Definition : Defn: A hydrous phosphate of iron of a blue to green color, growing darker on exposure. It occurs in monoclinic crystals, also fibrous, massive, and earthy.
Source : Webster's Unabridged Dictionary, 1913