Diópsido
system = Monoclinic twinning = Simple and multiple twins common on and cleavage = Distinct/good on fracture = Irregular/uneven, conchoidal tenacity = Brittle mohs = 5½ - 6½ Mindat page for Diopside luster = Vitreous to dull polish = refractive = n α = 1.663 - 1.699, n β = 1.671 - 1.705, n γ = 1.693 - 1.728 opticalprop = birefringence = δ = 0.030 dispersion = Weak to distinct, r>v pleochroism = fluorescence= absorption = streak = white gravity = density = 3.278 g/cm 3 melt = fusibility = diagnostic = solubility = diaphaneity = other = references = }} Diópsido es un mineral pyroxene monoclinic cuya composición es MgCaSi 2 O 6 . Posee una serie de solución completa con la hedenbergita (FeCaSi 2 O 6 ) y la augita , y soluciones solidas parciales con el ortopiroxeno y la pigeonita . Forma cristales de coloraciones variables, aunque tipicamente son de color verde opeaco en la clase prismatica monoclinic . Posee dos cleavages prismaticos distintivos en 87 y 93° tipicos de las series del piroxeno series. Su dureza Mohs es seis, y su dureza Vickers es 7.7 GPa bajo una carga de 0.98 N , y una gravedad especifica de 3.25 a 3.55. Es entre transparente y traslucido con un índice de refracción n α =1.663–1.699, n β =1.671–1.705, y n γ =1.693–1.728. Su ángulo óptico es entre 58° y 63°. El diópsido se encuentra en rocas igneas ultramafica s ( kimberlita y peridotita ), y la augita rica en diópsido es comun en rocas mafica s, tales como basalto olivine y andesita . El diópsido también se encuentra en un conjunto de rocas metamórficas, tales como en conmtacto con skarn s metamorficos desarrollados a partor de dolomita con un alto contenido de silicio.Es un mineral abundante en el mantle terrestre y es común en xenolito s peridotito erupted en kimberlita y basalto alkali. chrysotile (white asbestos ) by hydrothermal alteration and magmatic differentiation; it can react with hydrous solutions of magnesium and chlorine to yield chrysotile by heating at 600°C for three days. Some vermiculite deposits, most notably those in Libby, Montana , are contaminated with chrysotile (as well as other forms of asbestos) that formed from diopside. At relatively high temperatures, there is a miscibility gap between diopside and pigeonite , and at lower temperatures, between diopside and orthopyroxene . The calcium /(calcium+ magnesium + iron ) ratio in diopside that formed with one of these other two pyroxenes is particularly sensitive to temperature above 900°C, and compositions of diopside in peridotite xenoliths have been important in reconstructions of temperatures in the Earth's mantle . Gemstone quality diopside is found in two forms: the black star diopside and the chrome diopside (which includes chromium giving it a rich green colour). At 5.5–6.5 on the Mohs scale, chrome diopside is relatively soft to scratch. Mohs scale of hardness does not measure tensile strength or resistance to fracture. Violane is a manganese rich variety of diopside, violet to light blue in colour. Mindat page for Violane Chrome diopside ((Ca,Na,Mg,Fe,Cr) 2 (Si,Al) 2 O 6 ) is a common constituent of peridotite xenoliths, and dispersed grains are found near kimberlite pipes, and as such are a prospecting indicator for diamond s. Occurrences are reported in Canada, South Africa, Russia and a wide variety of other locations. Diopside was first described about 1800 and derives its name from the Greek dis , "twise", and òpsè , "face" in reference to the two ways of orienting the vertical prism. --> Referencias 1
- Hurlbut, Cornelius S.; Klein, Cornelis, 1985, Manual of Mineralogy , 20th ed., Wiley, pp 403-404, ISBN 0-471-80580-7
- Mindat: Diópsido
- Mindat: Diópsido del cromo, con locales
- Webmineral
- Galerias minerales
- Handbook of Mineralogy , Mineral Data Publishing, 2001, Diópsido versión PDF
- http://gemstone.org/gem-by-gem/english/diopside.html