from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A dark gray mineral, essentially Cu2S, that is an important ore of copper.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Cuprous sulphide, Cu2S, an important ore of copper.
from the GNU version of the Collaborative International Dictionary of English
- n. Native copper sulphide, called also copper glance, and vitreous copper; a mineral of a black color and metallic luster.
from The Century Dictionary and Cyclopedia
- n. A native copper sulphid (Cu2S), a mineral of a lead-gray to black color and metallic luster.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a heavy grey mineral that is an ore of copper
"chalcocite" of our present metallurgical science, which is a sulphide containing very nearly eighty per cent. of copper.
The copper in these deposits occurs as primary chalcopyrite (CuFeS2) or the important secondary copper mineral chalcocite (Cu2S).
In the easy recognition of the secondary copper sulphides, chalcocite, bornite, etc., the engineer finds a finger-post on the road to extension in depth; and the directions upon this post are not to be disregarded.
The essential fact appears to be that as enrichment progresses and chalcocite increases the process of enrichment becomes slower in action, and erosion may, in some circumstances, overtake it.
The primary copper mineral in the limestone is chalcocite, in exceptionally rich and solid masses, showing no evidence of having replaced earlier sulphides.
Copper is known to be taken into solution as copper sulphate at the surface, and to be redeposited as chalcocite where these sulphate solutions come in contact with chalcopyrite or pyrite below.
While some chalcocite is clearly the result of secondary enrichment from above, other chalcocite seems to have been related closely to the primary deposition.
In the United Verde Mine, oxidizing conditions at present prevail to the bottom of the chalcocite zone.
No traces of other primary minerals are present and the chalcocite here is regarded as probably primary.
It was formerly supposed that most of the chalcocite was of this origin; but as chalcocite is found in important amounts with enargite and chalcopyrite to great depths (now 3,500 feet), where the veins are still rich and strong, it begins to appear that much of the chalcocite is of primary origin.