Azurite elements

Copper is the 26th most abundant element on Earth, but it is rare to find pure metallic deposits. It is found in many different types of mineral ores, many of which are close to the surface and easy to extract. It is found in two types of ores (1) sulfide ores, such as covellite, chalcopyrite, bornite, chalcocite, and enargite and (2) oxidized ores, such as tenorite, malachite, azurite, cuprite, chrysocolla, and brochanite. 

Elemental composition Cu 57.47%, C 5.43%, H 0.91%, 0 36.18%. Both malachite and azurite may be identified by x-ray analysis and analyzed qualitatively using physical properties such as refractive index and density. For quantitative analysis, the compound may he digested in nitric acid and analyzed for copper by various instrumental methods (see Copper.)... 

Idiochromatic substances contain a specific coloring element, called a chro-mophore, which is part of their normal composition. The colors of idiochromatic materials tend to be constant and predictable. Examples of this are the minerals malachite and azurite, both carbonates of copper. These minerals are colored by the copper in their compositions, and are always green and blue, respectively. 

Some carbonate minerals are sources of important elements like zinc (smithsonite) and magnesium (magnesite). Other members of this group are used for carving and ornaments because of their striking colors and patterns. These include calcite, rhodochrosite, azurite, and malachite. 

Copper is a reddish metallic element (symbol Cu atomic no. 29). Its symbol derives from the Latin word cuprum, because it was originally discovered in Cyprus. It is widely found as different salts in minerals such as atacamite (chloride) azurite and malachite (carbonates) bornite, chalco-cite, chalcopjrite, stannite, tennantite, and tetrahedrite (sulfides) chalcanthite (sulfate) dioptase (silicate) erinite and olivenite (arsenates) tenorite (oxide) torbernite (phosphate) and zorgite (selenide). Copper is an essential constituent of several enzymes. It is carried in the blood by a specific copper-binding protein, ceruloplasmin. 

E27.2 Although copper is a relatively inert element, it does slowly oxidize on air, producing copper oxides (and upon longer exposure to the atmosphere, basic copper carbonates malachite and azurite). Both CU2O and CuO are basic oxides. Epidermis, the outermost layer of skin, is slightly acidic (pH about 5). When oxidized parts of the bracelet get in touch with acidic epidermis, a small amount of oxides dissolve and produce Cu, which is water soluble... 

Copper s relative abundance in the Earth s crust is about 50 mg/kg (i.e., ppm wt.), which is less than nickel and zinc. It occurs as a native element (4%), but the major part of its occurrence is as oxides minerals (10%) such as cuprite [Cu O, cubic] carbonates (5%) malachite [CuC03.Cu(OH)j, monoclinic] and azurite [2CuC03.Cu(0H)j, monoclinic] sulfide minerals (80%) chalcocite [Cu S, monoclinic], chalcopyrite [CuFeS, tetragonal], and bornite [CUjFeS, cubic] and in other rare minerals (1%) such as atacamite [CUjC OH), orthorhombic]. But only the oxide and sulfide minerals are used industrially as copper ores. Chile is the world s largest producer of copper, followed by the United States. 

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