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 pinkis ...

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. ( ...

. Copper is one of the few

metal A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typicall ...

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 Ore is natural rock or sediment that contains one or more valuable minerals, typically containing metals, that can be mined, treated and sold at a profit.Encyclopædia Britannica. "Ore". Encyclopædia Britannica Online. Retrieved 7 Apr ...

of copper in historic times and was used by pre-historic peoples. Native copper occurs rarely as isometric cubic and

octahedral In geometry, an octahedron (plural: octahedra, octahedrons) is a polyhedron with eight faces. The term is most commonly used to refer to the regular octahedron, a Platonic solid composed of eight equilateral triangles, four of which meet at ea ...

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 Tarnish is a thin layer of corrosion that forms over copper, brass, aluminum, magnesium, neodymium and other similar metals as their outermost layer undergoes a chemical reaction. Tarnish does not always result from the sole effects of oxygen in ...

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 produced b ...

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) ac ...

). 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 (molecule), wa ...

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 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." As o ...

(which is nicknamed the "

Copper Country The Copper Country is an area in the Upper Peninsula of Michigan in the United States, including Keweenaw County, Michigan, Houghton, Baraga and Ontonagon counties as well as part of Marquette County. The area is so named as copper mining was ...

" and "

Copper Island Copper Island is a local name given to the northern part of the Keweenaw Peninsula (projecting northeastward into Lake Superior at the western end of the Upper Peninsula of Michigan, United States of America), separated from the rest of the Kewe ...

") opened in the 1840s.

Isle Royale Isle Royale National Park is an American national park consisting of Isle Royale – known as Minong to the native Ojibwe – along with more than 400 small adjacent islands and the surrounding waters of Lake Superior, in the state of Michigan. ...

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 The Ontonagon River ( ) is a river flowing into Lake Superior at the village of Ontonagon, on the western Upper Peninsula of Michigan in the United States. The main stem of the river is long''The American Rivers Outstanding Rivers List'', Sec ...

, 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#Glaciology, ablation over many years, often Century, centuries. It acquires dis ...

is seen in the Ontonagon Boulder,

Ontonagon Boulder The Ontonagon Boulder (/ˌɒntəˈnɑːɡən ˈboʊldəɹ/) is a boulder of native copper originally found in the Upper Peninsula of Michigan, United States, and now in the possession of the Department of Mineral Sciences, National Museum of Na ...

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 geo ...

", 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 is ...

, 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 , nickname = , settlement_type = City , motto = ''Glück Auf'' (German language, German for ''Good luck'') , image_skyline = Welcome to tsumeb.jpg , imagesize = , image_caption ...

, 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 drywall. ...

, 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 population ...

, US File:Copper-Silver-39566.jpg, "Halfbreed" copper-silver nugget,

Keweenaw County, Michigan Keweenaw County (, ; , ) is a county in the Upper Peninsula of the U.S. state of Michigan, the state's northernmost county. As of the 2020 United States Census, the population was 2,046, making it Michigan's least populous county. It is also the ...

, US File:Native Copper from the Keweenaw Peninsula Michigan.jpg,

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 the ...

, US

References

External links

{{commons category Native element minerals Copper Cubic minerals Minerals in space group 225

Gallery

See also

References

Further reading

External links