Tetrahedrite
Pronunciation : Tet`ra*he"drite
Part of Speech : n.
Etymology : [So called because the crystals of the species are commonly tetrahedrons.] (Min.)
Definition : Defn: A sulphide of antimony and copper, with small quantities of other metals. It is a very common ore of copper, and some varieties yield a considerable presentage of silver. Called also gray copper ore, fahlore, and panabase.
Source : Webster's Unabridged Dictionary, 1913