'gray copper ore' definitions:

Definition of 'gray copper ore'

From: GCIDE

Tetrahedrite \Tet`ra*he"drite\, n. [So called because the crystals of the species are commonly tetrahedrons.] (Min.) 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. [1913 Webster]