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| Ophicalcite from Uzbek Republic |
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More Ophicalcite on ebay auction |
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Ophicalcite http://users.skynet.be/ A field trip is a great place to learn new words. Here is my newest one: "ophicalcite". Well calcite I knew of course - a white mineral, calcium carbonate, CaCO3 - but ophicalcite seemed to be something different. When I got home I consulted the Internet to get a better grip on this strange word. Ophicalcite seems to be a sort of Chinese drug to stop heavy bleeding. If I got it right it is also good for the liver, and the taste is sour. My searches on "ophicalcite" further lead me through some pages on ornamental stones like green Swedish marble and Connamara marble, but didn’t make me much wiser, so when the word "ophicalcite" finally brought me http://www.litosonline.com/ Thanks to the endless variety of colour shades, patterning and structure of the decorative stones used at stations on the Moscow Metro, a museum of "stone art" has been created which is without equal in the world. We are not talking of just a "veneer" but also a geological museum comprising several dozen varieties of rocks from more than 100 quarries. A far from complete list includes marble, dolomite, hard limestone, limestone, ophicalcite, onyx, travertine, serpentinite, granite, granodiorite, diorite, syenite, gabbro, anorthosite, gabbro-diabase, labradorite, basalt, teshenite, migmatite, gneiss, felsite tufa, quartzite, jasper, rhodonite, amazonite and wollastonite skarn. The walls and columns of the Metro stations are not just a "silent school" of aesthetic education, but also a school which could provide the basics of mineralogy and petrography within a fascinating historical-architectural framework. http://www.gsajournals.org/ Ophicalcite, a breccia of controversial origin composed of serpentinite fragments in pink calcite, caps paleotopographic ridges of ophiolite in Ligurian nappes of northern Italy. Abundant geopetal fabrics within the calcite suggest a sedimentary origin in contrast with previously proposed magmatic and hydrothermal origins. The restriction of ophicalcite to paleotopographic highs, upward increase in carbonate versus host rock, absence of fossils, and presence of caliche-like fabrics favor a pedogenic origin rather than an origin by recrystallization of pelagic ooze. Ultramafic rocks were thus subaerially exposed in certain areas prior to radiolarite deposition. If this interpretation is correct, certain long-held views of the environmental significance of ophiolite sequences should be re-evaluated. ....... http://www.1911encyclopedia. Certain calcareous metamorphic rocks frequently form stones which are sufficiently beautiful to be used for ornamental purposes, and are generally classed as marbles. Such serpentinous limestones are included by petrologists under the term " ophicalcite." The famous verde antico is a rock of this character. Mona marble is an ophicalcite from the metamorphic series of the Isle of Anglesey, while the " Irish green " of architects is a similar rock" from Connemara in western Galway. It is notable that some of the " white marble " of Connemara has been found by W. King and T. H. Rowney to consist almost wholly of malacolite, a silicate of calcium and magnesium. |
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