VARIEGAtEQ COPPER.-ORE. I 13 America.—‘ At Coqiiimbo in Chili, along with copper- green and malachite. Uses. Copper is extracted from it, but it is not so easily re duced as copper-glance. It yields from 50 to 70 per cent. of copper. Observations, 1. Its external characters and chemical composition, shew that it is a species intermediate between copper- glance and copper-pyrites. 2. It occurs equally abundant with copper-glance, but not in such great quantity as copper-pyrites. 3. This variety differs from copper-glance or vitreous copper-ore* with respect to its component parts, in con taining a smaller proportion of copper., and a greater proportion of iron. The variegated colour is sup- _ posed by Klaproth to be owing to the slightly oxidated state of the metal: so in steel, and other metallic sub stances, the beginning of their oxidation is indicated by a similar diversity of colours. In the last-mentioned sub stances, indeed, the change of colour is only superficial, for the oxygen of the atmosphere can only act upon the surface of the metal: in the variegated copper-ore, the diversity of colour penetrates the whole mass, in conse quence of the general distribution of the oxygen through out the substance of the ore. As, however, the oxida tion is slight, the metal is disposed to absorb a farther portion of oxygen ; and the uniform brown colour is Vol. III. H gradually