Malachite elements

Those dyes which, in contrast to malachite green and crystal violet, do not have the nitrogen in tertiary combination, for example, fuchsine, can lose water from their colour bases by direct elimination of its elements from their attachment to nitrogen and change into derivatives... 

Both Zn and Cu alloy with metaUic Fe. In silicates, Ctf and Zrf substitute for Fe and Mg in octahedral sites but the octahedral preference energy is small for Cu and zero for Z4, which, beyond their trace abundance in nature, explains why these two elements are not particularly abundant in any major FeMg-silicates. Cu and Zn form a very large number of sulfides (often in association with Fe) with Cu and Cu occupying either octahedral or tetrahedral sites. They also form scores of carbonates and hydroxides. Cu in chalcopyrite and Zn in sphalerite are tetrahedrally coordinated with S but other sulfides may contain trigonally coordinated metals. Cu in malachite and Zn in smithsonite are octahedrally coordinated with O. 

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.)... 

These minerals have never been mentioned as potential targets for luminescent sorting because of the absence of natural emission even under laser excitation. LIBS may be an excellent opportunity, because all those elements have strong and characteristic lines. Figure 8.17 present examples of malachite (Cu), galena (Pb), and sphalerite (Zn) breakdown spectra. 

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. 

In addition to the analysis of physical structural characteristics of textile fabric pseudomorphs, chemical information has been obtained. On bronze and copper artifacts, the pseudomorphs are composed of malachite, tenorite, and cuprite (I, 2), the formation of which probably requires moist conditions, a corrosive metal, and optimum fiber-metal contact (I). Trace elements in their structure vary from object to object and site to site (1-3), but the relationship of these elements and the fiber, metal, and soil composition is not yet known. 

The second phase of transition element discovery involved those which could readily be released from minerals through heating or reduction by hot charcoal. Again copper in the carbonate mineral malachite, silver in the sulfide mineral argentite and mercury as the sulfide in cinnabar might... 

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... 

He then examines some of the evidence regarding the validity of these assumptions. I might add parenthetically that in my own laboratory the analysis of a large munber of specimens of turquoise, a copj r phosphate mineral, which had been obtained from known mining areas, has demonstrated that Assumption (1) of Craddock s paper is true only in selected instances. Our analysis of other copper minerals like malachite also showed great trace element variance within a given source in several cases. 

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. 

Elements in nature can be found in different oxidation states. For example, the mineral cuprite has the formula Cu O. By rule 6, copper is in the +1 oxidation state. Malachite, on the other hand, has the formula CUjCOjlOHjj. Given that carbon is in the +4 state, each oxygen is in the -2 state, and each hydrogen is in the +1... 

The most important copper ores are chalcopyrite (CuFeS2) and malachite [Cu2(0H)2C03], Copper ores often occur near deposits of elemental copper, providing early humans with an easy way to locate copper ores. The electrometallurgical production of pure copper from chalcopyrite is described in Section 23.3. 

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