The Mineral copper
Copper is one of the most famous and useful metals, and has been important since ancient civilizations for ornaments and coinage. Its complex crystals can be beautifully formed in odd and unique masterpieces that are treasured by collectors.
Copper may have impurities, but is commonly in a fairly pure state. Native copper is found only in small quantities throughout the world, but there are a few areas that are rich in findings, such as the Keweenaw Peninsula in Michigan. Well crystallized specimens are not common, and are very much sought after. The interlocking Copper and Silver masses that are commonly found in the Keweenaw Peninsula are known as "Halfbreeds".
Some Copper on the mineral market has been cleaned and shined using various solvents. These forms are Copper can easily be spotted as their copper-red color is almost artificial looking in its fleshy hue.
For additional information, see the gemstone section on Copper.
Copper-red to brown. Tarnishes green, sometimes also blue, brown, red, or black.
Copper-red. Streak shiny.
2.5 - 3
Ductile and Malleable
|Other ID Marks
1) Tarnish. Green tarnish speckled throughout a specimen, may also be blue, red, or black.
2) Excellent conductor of electricity. Copper is the second best conductor of electricity (after Silver).
Often found as distorted masses or extremely distorted crystals. Crystals, which are uncommon, are usually cubic or dodecahedral with modified faces. Octahedral crystals do occur, but are very rare. Also occurs as flattened crystals, scales, dendrites, and wires.
A natural mixture of Copper and Silver. Also the term describing an alloy of copper and silver.
Native Copper was the only source of copper until the turn of the century, when extraction methods were improved. The copper ores are far more abundant than Native Copper, and are the main source of copper today. Even though, Native Copper is sometimes mined on its own for the copper content. Copper ranks second as the most-used metal in the world. The special properties of conductivity, malleability, resistance, and beauty make it so popular. The main uses of copper are electrical. Due to the greatness of copper's conductivity, which offers the lowest electrical resistance after silver. Copper is very ductile and can be drawn into very thin wires, which serves as its primary electrical function. It is used for electrical machinery such as motors, electromagnets, generators and communication devices.
Copper has been fashioned into ornamental objects and cooking utensils since the beginning of mankind. Coins have also been made of copper throughout history. Copper is also used in pigments, insecticides, and fungicides, although it has of lately been largely replaced by synthetic chemicals.
Two important alloys are formed from copper. Brass is an alloy of copper and zinc, and bronze is an alloy of copper and tin. U.S. pennies were made out of copper until 1982, when the cost of copper exceeded the value of the penny. Since 1982, pennies are now from zinc and are only plated with copper.
The mines in the Keweenaw Peninsula in Michigan and the surrounding area (Houghton, Ontonagon, and Keweenaw Counties) produce the greatest abundance of the mineral Copper, and are the best-known locality of this mineral. The specific localities are too numerous to name, although some of the more well-known areas are Caledonia, Calumet, Centennial, Copper Falls, Hancock, Kearsage, Osceola, Mohawk, Phoenix, and White Pine.
Arizona also has several famous copper localities, specifically Ajo, Pima Co.; Morenci, Greenlee Co.; and Ray, Pinal Co. Bisbee, Cochise Co. is a very famous locality and has one of the world's largest copper mines, although mostly ore came out of this mine and Native Copper was comparatively scarce. Copper specimens from Bisbee are very highly valued. In the Northeastern U.S., Copper is known from the Chimney Rock Quarry, Bound Brook, Somerset Co., New Jersey.
Famous worldwide localities include Broken Hill, New South Wales, Australia; Daye, Hubei Province, China; Chengmenshan, Jiurui, Jiangxi Province, China; Ogonja, Namibia; and the Callington District, Cornwall, England. Of interesting note is Corocoro, La Paz , Bolivia, where odd pseudomorphs of Copper after Aragonite have been found. Recently popular occurrences are the Itauz Mine, Dzezkazgan, Kazakhstan, where very intricate dendritic crystals have been found; and the Rubtsovoskoe Mine, near Poteryaevka, Altai, Russia, which provides complex crystal forms. The ever-famous Tsumeb Mine in Tsumeb, Namibia, has also produced Native Copper, and these are very highly cherished by mineral collectors.
Well-known Canadian occurrences of Copper are the Afton Mine, Kamloops, British Columbia; and Mamainse Point, Algoma District, Ontario.
Distingushing Similar Minerals
The distinctive habits of Copper can usually distinguish it from all other minerals.