Everyone knows copper is an incredibly valuable industrial metal, but not everyone knows that it’s found in different kinds of rocks all around the world.
In this article, we’ll give a brief overview of rocks that contain copper, why they contain copper, and where you can find these rocks.
6 Rocks That Contain Copper
The first rock we’ll cover in this article is chalcopyrite, which is one of the major ores of copper.
It is found most often in veins of sulfide and igneous rocks. Its chemical composition consists of copper, iron, and sulfur, abbreviated as CuFeS2.
To identify chalcopyrite, look for a brass-yellow, opaque rock with a metallic luster.
Chalcopyrite ranks at 3.5-4 on the Mohs hardness scale, and has an indistinct cleavage. It also has a tetragonal crystal system.
Because chalcopyrite is one of the most common rocks containing copper, it is found in nearly every copper mine around the globe.
However, the mines that uncover chalcopyrite most frequently are in the Bolognesi Province, Recuay Province, and Angaraes Province of Peru, as well as mines in Connecticut, New York, New Mexico, and Kentucky in the United States.
Bornite is arguably the second most important ore of copper, following chalcopyrite.
It’s chemical formula is Cu5FeS4, and it is typically found as a large metallic material in igneous, metamorphic, and sedimentary rocks.
It is also often found in hydrothermal vents.
The color of bornite ranges dramatically.
Before being exposed to air, it is a copper red or brown, but after being exposed it quickly turns to a metallic purple color.
Bornite rates 3 on the Mohs hardness scale, has an indistinctive cleavage, and an orthorhombic crystal structure.
Just like chalcopyrite, bornite can be found in most coper mines.
The most notable are in Peru, the southern coast of Australia, in the Yukon, Canada, and throughout most of the states in the contiguous United States.
Azurite, and the rest of the rocks in this article, are secondary copper minerals.
The chemical formula for azurite is Cu3(CO3)2(OH)2, and is formed by carbonated water acting on copper containing minerals.
This means that azurite is mostly found in the oxidized portions of copper deposits.
As indicated by the name, azurite tends to be a beautiful azure blue, but can be found in all shades of blue.
The stone is transparent, with perfect cleavage and a monoclinic crystal system.
It ranks at 3.5-4 on the Mohs hardness scale.
In the United States, the best places to find azurite are New Mexico, Arizona, and Utah.
Other important and noteworthy deposits have been found in France, Namibia, Russia, Chile, and Australia.
Malachite is a very common secondary copper mineral.
Its chemical formula is Cu2(CO3)(OH)2.
Malachite is an opaque rock with a silky luster that can be any color from bright green and yellow to a dark green that is nearly black.
Malachite is a 3.5-4 on the Mohs scale, has a monoclinic crystal system, and perfect cleavage.
This is the most commonly found rock in the oxidized zones of copper deposits.
Look for malachite in the Juab County, Utah, U.S.A, the Morenci, Greenlee, Globe, Ajo, and Pima Counties in Arizona, U.S.A., and the Grant and Socorro Counties in New Mexico, U.S.A.
Malachite can also be found in large deposits in Congo, Zambia, Australia, and most of all, Russia.
Chalcocite is another secondary mineral of copper.
Cu2S is its chemical formula.
Chalcocite can be identified by its metallic luster and it’s blue-grey, black-grey, and steel-grey color.
As opposed to the rest of the rocks in this article, chalcocite only reaches a 2.5-3 on the Mohs hardness scale, but it, too, has a monoclinic crystal system and indistinct cleavage.
Chalcocite is very common and can be found in Pennsylvania, Virginia, Texas, Arizona, and California in the United States.
It can also be found in Australia, Russia, and, believe it or not, the coasts of Antarctica.
The last rock we’ll cover in this article is another secondary ore of copper, covellite.
Covellite’s chemical formula is CuS, and is by far the softest of all the rocks mentioned, reaching only 1.5-2 on the Mohs hardness scale.
Covellite can be found as a dark blue sub-metallic mass, sometimes with crystals exposed to the surface, though perfect crystals are very rare.
It is also iridescent, and you can often see either purple, deep red, or brass-yellow reflections in the rock.
It is opaque, and has a hexagonal crystal system with perfect cleavage.
Although covellite was first discovered in Italy and can still be found there, the absolute best place to find samples is Butte, Montana.
It is also abundant in Bolivia and Chile.
There you have it!
Copper is mined from all sorts of rocks and minerals which can be found pretty much everywhere!
I hope this article has shed some light on where copper comes from and where you can find these samples for yourself.
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