Muscovite mica

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Transcript of Muscovite mica


2. What is Mica? Mica is a generic term applied to a group of rock-forming complexaluminosilicate minerals having a sheet or plate like structure with varyingchemical composition and physical properties. 3. Types Of MicaOf the nine common varieties in the mica group of minerals, the two principalclasses of Mica types of commercial importance are Muscovite : K Al2 (Al Si3 O10 )(OH) 2 and Phlogopite : K Mg3 (Al Si3O10 )(OH) 2 4. Muscovite Mica It is a hydrous potassium aluminium silicate with a predominance ofpotassium. It ranges from colourless through browns to greens or reds. 5. Phlogopite Mica It is a hydrous magnesium aluminium silicate with a predominance ofmagnesium. It is commonly called as Amber Mica which varies in colourfrom light silver to dark brown or amber. 6. OccurenceMuscovite is the most common mica, found in Granites,Pegmatites, Gneisses, and Schists, and as a contactmetamorphic rock or as a secondary mineral resultingfrom the alteration of Topaz, Feldspar, Kyanite, etc.In Pegmatites, it is often found in immense sheets thatare commercially valuable. 7. Exploration and exploitation is successfully carriedby means of systematic vertical shaft and open castmining. The principal muscovite mica deposits arechiefly found in the States of Jharkhand, Rajasthanand Andhra Pradesh. Jharkhand (formerly Bihar State) which produces theworld's finest muscovite mica well known throughoutthe globe 8. MuscoviteMica may bedivided into twocolor groups :RUBY MUSCOVITEGREEN MUSCOVITE 9. Ruby MuscoviteColour ranges from an almost whitethrough pink to a light ruby andinto shades of brownish ruby andbrown. It is produced in the IndianStates of Jharkhand and Rajasthan. 10. Green MuscoviteRanges from light to pale green through yellowishand olive green to a dark green. It is producedin the Indian State of Andhra Pradesh. 11. Physical Properties Lustre -Vitreous, Silky, Pearly Diaphaneity (Transparency):Transparent,Translucent 12. Colour:White to colorless, silvery-white, and tinged various colors byimpurities. Streak:White Hardness (Mohs): 2 13. Cleavage:PerfectPerfect on {001}. Fracture:Micaceous Crystal System: Monoclinic witha = 5.199, b = 9.027, c = 20.106 = 95.78 14. DISTINGUISHING SIMILAR MINERALS Chlorite and Margarite - Not as elastic as Muscovite. Biotite, Phlogopite - Usually darker in color, otherwise very difficult todistinguish. Lepidolite - Very difficult to distinguish from pink Muscovite. Gypsum - Cannot be peeled into micaceous sheets, crystals usuallydifferently shaped. 15. Uses 16. THANK YOU 17. Muscovite is an extremely common mineral, some bright yellow and others with perfectstar formations, come from the famous pegmatite localites in the Doce andJequitinhonha Valleys in Minas Gerais Brazil. Specific localities include Divino dasLaranjeiras ("stars"),Galileia, Governador Valadares, Conselheiro Pena, Jaguaracu,Aracuai, and Coronel Murta. Beautiful yellow Muscovite comes from the Davib Ost Farm,Karibib, Erongo, Namibia. Fine Muscovite plates, often associated withvaluable pegmatitegemstones, come from the Shigar Valley and Skardu District inNorthern Pakistan. Nellore, India, is famous for its Muscovite mines which have producedsome of the worlds largest mica sheets. Xuebaoding Mountain, Pingwu, in SichuanProvince, China, provides excellent Aquamarine and Scheelite that are associated withbeautiful Muscovite plates.In the U.S., Muscovite is fairly common in the pegmatites of San Diego county, includingPala and Ramona. Rare Muscovitepseudomorphs after Tourmaline come from the WillowSpring Ranch, Oracle, Pinal Co., Arizona. A bright pink, lithium-rich variety comes from theHarding Mine, Taos Co., New Mexico; and gemmy green crystals from Lincoln Co., NorthCarolina. Other important localties include Mt Antero, Chaffee Co., Colorado; theDiamond Mica Mine, Keystone, Pennington Co., South Dakota; Shelby, Cleveland Co.,North Carolina; and Bedford, Westchester Co., New York.New England contains some important Muscovite in its famous pegmatites, specifically atMiddlesex Co., Connecticut (East Hampton, Haddam, and Portland); Grafton Co., NewHampshire (the Palermo No. 1 Mine, Groton; and the Ruggles Mine, Grafton); Mt. Apatite,Auburn, Androscoggin Co., Maine; and Greenwood and Newry, Oxford Co., Maine.