Native copper is an
uncombined form of
copper
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pink ...
that occurs as a natural
mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2 ...
. Copper is one of the few
metal
A metal (from ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electrical resistivity and conductivity, e ...
lic
elements to occur in
native form, although it most commonly occurs in
oxidized
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a ...
states and mixed with other elements. Native copper was an important
ore of copper in historic times and was used by pre-historic peoples.
Native copper occurs rarely as isometric cubic and
octahedral crystals, but more typically as irregular masses and
fracture fillings. It has a reddish, orangish, and/or brownish color on fresh surfaces, but typically is
weathered
''Weathered'' is the third studio album by American rock band Creed, released on November 20, 2001. It was the last Creed album to be released until '' Full Circle'' came out in October 2009, with Creed disbanding in June 2004. It is the only Cr ...
and coated with a green
tarnish of
copper(II) carbonate
Copper(II) carbonate or cupric carbonate is a chemical compound with formula . At ambient temperatures, it is an ionic solid (a salt) consisting of copper(II) cations and carbonate anions .
This compound is rarely encountered because it is di ...
(also known as
patina
Patina ( or ) is a thin layer that variously forms on the surface of copper, brass, bronze and similar metals and metal alloys ( tarnish produced by oxidation or other chemical processes) or certain stones and wooden furniture (sheen produce ...
or
verdigris
Verdigris is the common name for blue-green, copper-based pigments that form a patina on copper, bronze, and brass. The technical literature is ambiguous as to its chemical composition. Some sources refer to "neutral verdigris" as copper(II) ...
). Its
specific gravity
Relative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water at its dens ...
is 8.9 and its
hardness
In materials science, hardness (antonym: softness) is a measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion. In general, different materials differ in their hardness; for example hard ...
is 2.5–3.
The mines of the
Keweenaw
The Keweenaw Peninsula ( , sometimes locally ) is the northernmost part of Michigan's Upper Peninsula. It projects into Lake Superior and was the site of the first copper boom in the United States, leading to its moniker of "Copper Country." As ...
native copper deposits of
Upper Michigan
The Upper Peninsula of Michigan – also known as Upper Michigan or colloquially the U.P. – is the northern and more elevated of the two major landmasses that make up the U.S. state of Michigan; it is separated from the Lower Peninsula by ...
were major copper producers in the 19th and early 20th centuries, and are the largest deposits of native copper in the world.
[ (Web archive; click cancel when it asks for authentication.)] Native Americans mined copper on a small scale at this and many other locations,
and evidence exists of copper trading routes throughout North America among native peoples, proven by isotopic analysis. The first commercial mines in the
Keweenaw Peninsula
The Keweenaw Peninsula ( , sometimes locally ) is the northernmost part of Michigan's Upper Peninsula. It projects into Lake Superior and was the site of the first copper boom in the United States, leading to its moniker of " Copper Country." A ...
(which is nicknamed the "
Copper Country" and "
Copper Island") opened in the 1840s.
Isle Royale in western Lake Superior was also a site of many tons of native copper. Some of it was extracted by native peoples, but only one of several commercial attempts at mining turned a profit there.
An archived record of native copper originally found up river from
Lake Superior
Lake Superior in central North America is the largest freshwater lake in the world by surface areaThe Caspian Sea is the largest lake, but is saline, not freshwater. and the third-largest by volume, holding 10% of the world's surface fresh wa ...
, on the west branch of the
Ontonagon River, via being dragged by a
glacier
A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such a ...
is seen in the Ontonagon Boulder,
Ontonagon Boulder now in the possession of the Department of Mineral Sciences, National Museum of Natural History, Smithsonian Institution.
Another major native copper deposit is in
Coro Coro, Bolivia.
The name copper comes from the
Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
''kyprios'', "of
Cyprus
Cyprus ; tr, Kıbrıs (), officially the Republic of Cyprus,, , lit: Republic of Cyprus is an island country located south of the Anatolian Peninsula in the eastern Mediterranean Sea. Its continental position is disputed; while it is ...
", the location of copper mines since pre-historic times.
Gallery
File:Copper-20856.jpg, Broken Hill, New South Wales
Broken Hill is an inland mining city in the far west of outback New South Wales, Australia. It is near the border with South Australia on the crossing of the Barrier Highway (A32) and the Silver City Highway (B79), in the Barrier Range. It i ...
, Australia
File:Copper-130051.jpg, Native copper cementing host rock, Ray Mine, Arizona
File:Copper-20862.jpg, Itauz Mine, Kazakhstan
Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbeki ...
File:Copper-18705.jpg, Tsumeb, Namibia
File:Copper-Gypsum-177370.jpg, Dendritic native copper encased in transparent gypsum
Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and drywa ...
, Mission Mine, Pima County, Arizona
Pima County ( ) is a county in the south central region of the U.S. state of Arizona. As of the 2020 census, the population was 1,043,433, making it Arizona's second-most populous county. The county seat is Tucson, where most of the populati ...
, US
File:Copper-Silver-39566.jpg, "Halfbreed" copper-silver nugget, Keweenaw County, Michigan, US
File:Native Copper from the Keweenaw Peninsula Michigan.jpg, Keweenaw Peninsula
The Keweenaw Peninsula ( , sometimes locally ) is the northernmost part of Michigan's Upper Peninsula. It projects into Lake Superior and was the site of the first copper boom in the United States, leading to its moniker of " Copper Country." A ...
, Michigan
Michigan () is a state in the Great Lakes region of the upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the 10th-largest state by population, the 11th-largest by area, and t ...
, US
See also
*
*
*
*
*
References
Further reading
*Thurner, Arthur W. ''Strangers and Sojourners - A History of Michigan's Keweenaw Peninsula'' (Detroit, Michigan, U.S.A.: Wayne State University Press, 1994) .B
*
External links
{{commons category
Native element minerals
Copper
Cubic minerals
Minerals in space group 225