LIKE,SHARE,COMMENT facebook/medicinestones MINERALS & PHYSICAL PROPERTIES Azurite - Cu3(CO3) 2(OH)2 Name: From the Persian lazhward, for its characteristic blue color. Occurrence: In the oxidized zones of copper deposits associated with carbonate rocks; may constitute an ore of copper. Association: Malachite, chrysocolla, brochantite, antlerite, cuprite, cerussite, smithsonite, calcite, dolomite. Distribution: Widespread, with many localities producing good crystals. From Chessy, near Lyon, Rhˆone, France, Zambia, USA, Mexico, China, Australia, Namibia, Morocco, Crystal Data: Monoclinic. Point Group: 2/m. Crystals are typically complex, with over 100 forms recorded, to 30 cm. Tabular on {001}, less commonly so on {102} or {102}; short to long prismatic along [001], with prominent {110} and {100}, or along [010], with wedgelike terminations. As rhomboidal, lenticular, or spherical subparallel aggregates, which may form rosettes; also as internally radial stalactitic or columnar aggregates; botryoidal, drusy, earthy, massive. Twinning: Rare; twin planes {101}, {102}, {001}. Physical Properties: Cleavage: On {011}, perfect but interrupted; on {100}, fair; on {110}, poor. Fracture: Conchoidal. Tenacity: Brittle. Hardness = 3.5–4 D(meas.) = 3.773(3)D(calc.) = 3.78 Optical Properties: Transparent to translucent. Streak: Pale blue. Luster: Vitreous to subadamantine. Color: Azure-blue, Berlin blue, very dark to pale blue; pale blue in transmitted light. The optical properties (color, intensity) of minerals such as azurite and malachite are explained in the context of conventional electronic spectroscopy of coordination complexes. Relatively detailed descriptions are provided by ligand field theory. Optical Class: Biaxial (+). Pleochroism: In shades of blue. Orientation: X = b; Z ∧ c = –12◦360. Dispersion: r > v, strong. Absorption: Z >Y >X. α = 1.730 β = 1.754–1.758 γ = 1.835–1.838 2V(meas.) = 67◦ Cell Data: Space Group: P21/c. a = 5.0109(5) b = 5.8485(6) c = 10.345(2)β = 92.43(3)◦Z=2 X-ray Powder Pattern: Tsumeb, Namibia. 3.516 (100), 2.224 (70), 5.15 (55), 3.674 (50), 2.510 (35), 2.287 (35), 5.08 (30) Dana Class: 16a.02.01.01 (16a) Carbonates - Hydroxyl or Halogen (16a.02)where (A B)3 (XO3)2 Zq (16a.02.01) Dana Group 16a.02.01.01 Azurite Cu3(CO3)2(OH)2 P 21/a 2/m Strunz Class: 05.BA.05 05 - CARBONATES (NITRATES) 05.B - Carbonates with additional anions, without H2O 05.BA -With Cu, Co, Ni, Zn, Mg, Mn 05.BA.05 Azurite Cu3(CO3)2(OH)2 P 21/a 2/m Weathering: Azurite is unstable in open air with respect to malachite, and often is pseudomorphically replaced by malachite. This weathering process involves the replacement of some the carbon dioxide (CO2) units with water (H2O), changing the carbonate:hydroxide ratio of azurite from 1:1 to the 1:2 ratio of malachite: 2 Cu3(CO3)2(OH)2 + H2O → 3 Cu2(CO3)(OH)2 + CO2 From the above equation, the conversion of azurite into malachite is attributable to the low partial pressure of carbon dioxide in air. Azurite is also incompatible with aquatic media, such as saltwater aquariums. Electron Density: Bulk Density (Electron Density)=3.67 gm/cc. Note: Specific Gravity of Azurite =3.83 gm/cc. Fermion Index: Fermion Index = 0.0009457773 Boson Index = 0.9990542227 Photoelectric: PEAzurite = 24.43 barns/electron U=PEAzurite x rElectron Density= 89.58 barns/cc. Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units) Azurite is Not Radioactive
Posted on: Fri, 14 Mar 2014 06:47:06 +0000
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