Copper | |
---|---|
General | |
Category | Native metal |
Formula (repeating unit) | Cu |
Strunz classification | 01.AA.05 |
Dana classification | 1.1.1.3 |
Crystal system | Cubic |
Crystal class | Hexoctahedral (m3m) H-M symbol: (4/m 3 2/m) |
Space group | Fm3m |
Unit cell | a = 3.615 Å; Z = 4 |
Identification | |
Color | Pale rose on fresh surface, quickly darkens to copper-red; in reflected light, pale rose |
Crystal habit | As cubes, dodecahedra, and as tetrahexahedra; rarely as octahedra and complex combinations. Commonly flattened on {111}, elongated along [001]. Also as irregular distortions, in twisted, wirelike shapes; filiform, arborescent, massive |
Twinning | On {111} to produce simple contact and penetration twins and cyclic groups |
Cleavage | None |
Fracture | Hackly - jagged |
Tenacity | Highly malleable and ductile |
Mohs scale hardness | 2+1⁄2–3 |
Luster | Metallic |
Streak | Copper-red |
Diaphaneity | Opaque |
Specific gravity | 8.95 |
Solubility | Soluble in nitric acid |
Other characteristics | Tarnishes to black or green in air. |
References | [1] [2] [3] [4] |
Native copper is an uncombined form of copper that occurs as a natural mineral. Copper is one of the few metallic elements to occur in native form, although it most commonly occurs in oxidized 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 and coated with a green tarnish of copper(II) carbonate (also known as patina or verdigris). Its specific gravity is 8.9 and its hardness is 2.5–3. [5]
The mines of the Keweenaw 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. [6] Native Americans mined copper on a small scale at this and many other locations, [7] 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 (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. [6] An archived record of native copper originally found up river from Lake Superior, on the west branch of the Ontonagon River, via being dragged by a glacier is seen in the 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 kyprios, "of Cyprus", the location of copper mines since pre-historic times. [3]
Ore is natural rock or sediment that contains one or more valuable minerals concentrated above background levels, typically containing metals, that can be mined, treated and sold at a profit. The grade of ore refers to the concentration of the desired material it contains. The value of the metals or minerals a rock contains must be weighed against the cost of extraction to determine whether it is of sufficiently high grade to be worth mining and is therefore considered an ore. A complex ore is one containing more than one valuable mineral.
The Upper Peninsulaof Michigan—also known as Upper Michigan or colloquially the U.P. or Yoop—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 the Straits of Mackinac. It is bounded primarily by Lake Superior to the north, separated from the Canadian province of Ontario at the east end by the St. Marys River, and flanked by Lake Huron and Lake Michigan along much of its south. Although the peninsula extends as a geographic feature into the state of Wisconsin, the state boundary follows the Montreal and Menominee rivers and a line connecting them.
Turquoise is an opaque, blue-to-green mineral that is a hydrous phosphate of copper and aluminium, with the chemical formula CuAl6(PO4)4(OH)8·4H2O. It is rare and valuable in finer grades and has been prized as a gemstone for millennia due to its hue.
Ontonagon County is a county in the Upper Peninsula of the U.S. state of Michigan. As of the 2020 census, the population was 5,816, making it Michigan's third-least populous county. The county seat is Ontonagon. The county was set off in 1843, and organized in 1848. Its territory had been organized as part of Chippewa and Mackinac counties. With increasing population in the area, more counties were organized. After Ontonagon was organized, it was split to create Gogebic County. It is also the westernmost county in United States that lies within the Eastern Time Zone.
Keweenaw County is a county in the western Upper Peninsula of the U.S. state of Michigan. As of the 2020 census, the county's population was 2,046, making it Michigan's least populous county. It is also the state's largest county by total area, including the waters of Lake Superior, as well as the state's northernmost county. The county seat is Eagle River.
The Keweenaw Peninsula is a peninsula of the U.S. state of Michigan. Part of the greater landmass of the Upper Peninsula, the Keweenaw Peninsula projects about 65 miles (105 km) northeasterly into Lake Superior, forming Keweenaw Bay. The peninsula is part of Michigan's Copper Country region, as the region was home to the first major copper mining boom in the United States. Copper mining was active in this region from the 1840s to the 1960s.
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 prevalent there from 1845 until the late 1960s, with one mine continuing through 1995. The region includes Copper Island, Copper Harbor and Isle Royale. In its heyday in the latter half of the 19th century and the early 20th century, the area was the world's greatest producer of copper.
Douglass Houghton was an American geologist and physician, primarily known for his exploration of the Keweenaw Peninsula of Michigan. It was the site of a copper boom and extensive copper mining beginning in the 19th century. He was appointed in 1839 as the first state geologist of Michigan, after it was admitted to the union, and served in that position for the rest of his life.
The Minesota Mine is a former copper mine near Rockland, Ontonagon County in the Upper Peninsula of the U.S. state of Michigan. The Minesota was one of the most productive and famous early mines in the Michigan Copper Country.
Keweenaw National Historical Park is a unit of the U.S. National Park Service. Established in 1992, the park celebrates the life and history of the Keweenaw Peninsula in the Upper Peninsula of the U.S. state of Michigan. It is a federal-local cooperative park made up of two primary units, the Calumet Unit and the Quincy Unit, and almost two dozen cooperating "Heritage Sites" located on federal, state, and privately owned land in and around the Keweenaw Peninsula. The National Park Service owns approximately 1,700 acres (690 ha) in the Calumet and Quincy Units. Units are located in Baraga, Houghton, Keweenaw, and Ontonagon counties.
This is a list of the National Register of Historic Places listings in Houghton County, Michigan.
A native metal is any metal that is found pure in its metallic form in nature. Metals that can be found as native deposits singly or in alloys include antimony, arsenic, bismuth, cadmium, chromium, cobalt, indium, iron, manganese, molybdenum, nickel, niobium, rhenium, tantalum, tellurium, tin, titanium, tungsten, vanadium, and zinc, as well as the gold group and the platinum group. Among the alloys found in native state have been brass, bronze, pewter, German silver, osmiridium, electrum, white gold, silver-mercury amalgam, and gold-mercury amalgam.
In the United States, copper mining has been a major industry since the rise of the northern Michigan copper district in the 1840s. In 2017, the US produced 1.27 million metric tonnes of copper, worth $8 billion, making it the world's fourth largest copper producer, after Chile, China, and Peru. Copper was produced from 23 mines in the US. Top copper producing states in 2014 were Arizona, Utah, New Mexico, Nevada, and Montana. Minor production also came from Idaho and Missouri. As of 2014, the US had 45 million tonnes of known remaining reserves of copper, the fifth largest known copper reserves in the world, after Chile, Australia, Peru, and Mexico.
The Ontonagon Boulder is a 3,708 pounds (1,682 kg) 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 Natural History, Smithsonian Institution. In 1843 the boulder was purchased from a local entrepreneur and shipped to Washington D.C.
In Michigan, copper mining became an important industry in the 19th and early 20th centuries. Its rise marked the start of copper mining as a major industry in the United States.
The Nonesuch Shale is a Proterozoic geologic formation that outcrops in Michigan and Wisconsin, United States, but has been found by drill holes to extend in the subsurface as far southwest as Iowa.
The Calumet Historic District is a National Historic Landmark District that encompasses most of the village of Calumet, Michigan. The district was designated in 1989 for the community's importance in the history of the region's copper mining industry.
Coloradoite, also known as mercury telluride (HgTe), is a rare telluride ore associated with metallic deposit. Gold usually occurs within tellurides, such as coloradoite, as a high-finess native metal.
The Victoria Mine is the name given to a series of copper mines located in Rockland Township, Ontonagon County, in Michigan's Copper Country. It was near this location that a large piece of float copper, known as the Ontonagon Boulder, was found. The mine operated off and on from 1849 until its final closure in 1921. Most of the metal found there was low grade native copper from the Forest Lode. Quartz, epidote, calcite, prehnite, and pumpellyite are also found in the rock.