Chalcocite Facts

Chalcocite Facts
One of the most important ores of the copper mineral is chalcocite, and compared to other ores it has the most benefits. Chalcocite has a content of high copper, and copper can be easily separated from sulfur. Chalcocite is very scarce, and it is formed from the mineral's alteration of primary copper attacked by oxygen. The color of chalcocite may be black or blackish-grey, with a grayish black streak, metallic luster, and poor cleavage. On the Mohs Hardness scale, it scores between 2.5 to 3.0 and has a specific gravity of 5.5 to 5.8. Its diagnostic properties include its color, plus its soft and sooty appearance. The chemical composition of chalcocite is copper sulfide with a crystal system that is monoclinic.
Interesting Chalcocite Facts:
The name chalcocite comes from an alteration of the obsolete name chalcosine, from the Greek "khalkos" or "chalkos" meaning copper.
Chalcocite is sometimes known as redruthite, ducktownite, vitreous copper, and copper-glance.
At times, chalcocite may be found as a primary vein mineral in hydrothermal veins. Most chalcocite though occurs in the supergene enriched environment below the oxidization zone of copper deposits.
Chalcocite is usually found in sedimentary rocks.
The mining of chalcocite has taken place for centuries and is one of the most profitable ores due to its high copper content, which is nearly 80% by weight.
Chalcocite has been known to form pseudomorphs of the minerals chalcopyrite, pyrite, enargite, bornite, covellite, millerite, galena and sphalerite.
Pseudomorphs are minerals that replace other minerals atom by atom, though leaves intact the original mineral's crystals shape.
Chalcocite is a prized possession for mineral collectors and some will command extremely high prices, especially when in good crystals.
Chalcocite is found nearly all over the world. A classic locality for chalcocite is Cornwall, England, and large, well-formed crystals have come from Australia.
In China, and odd new form of the mineral has been found with iridescent root-like growths.
In the United States, the best specimens of chalcocite had come from mines in Connecticut. Other localities include those in Montana, Wisconsin, New Mexico, New Jersey, and a few others.
The minerals commonly associated with chalcocite include calcite, galena, quartz, chrysocolla, malachite, and bornite.
Similar but distinguishing minerals include galena, which have different crystals and cleavage; and acanthite, which is more sectile.

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