Copper is a metal, which first became known to mankind for several millennia BC. In nature, it is usually found in the form of nuggets or in the mineral composition. Copper colour range varies from grayish brown to goldish with pinky shade. Some other reddish shades are also possible.
The fields of application of this metal are almost universal: electrical and mining engineering, chemical and automotive industries and many others as well. Copper-gold alloys are often used in jewelry to increase the strength of products offerings to deformation and abrasion, as pure gold is a very soft metal, also vulnerable to physical impact.
The extraction of copper ore and its further processing is a labour-intensive process, which is due to the fact that the copper content in the ore is usually very low. Another problem is that the metal often occurs in conjunction with zinc, lead, gold or silver. This fact inevitably affects the complexity of the treatment process.
One of the world's best collections of native copper is presented in the Mining Museum in Saint-Petersburg. Among its artefacts is a stone weighing 842 kg, which is the largest of the copper nuggets found in Russia, a gift to the Mining Museum from the Emperor Alexander II (1858).
Copper. An intergrowth of large crystals Keweenaw, Michigan, USA
Copper. Dendrite, Michigan, USA
Dendrite with malachite Belousovsky Mine, Altai. A present of the Privy Councillor Prof.P.V.Eremeev, 1896
Copper. Intergrowth of dendrite with green copper, Turinskie mines, the Urals.
