Natural sillimanite is used in the manufacture of high alumina refractories or 55–60% alumina bricks. However, it has mostly been replaced by the other aluminosilicate polymorphs, andalusite and kyanite, for this purpose.[9] As of 1998[update], sillimanite was just 2% of all aluminosilicate mineral production in the western world.[10]
^MacKenzie, W. S.; Guilford, C. (1980). Atlas of rock-forming minerals in thin section. Essex: Longman Scientific & Technical. p. 10. ISBN0-582-45591-X.
^Whitney, D.L. (2002). "Coexisting andalusite, kyanite, and sillimanite: Sequential formation of three Al2SiO5 polymorphs during progressive metamorphism near the triple point, Sivrihisar, Turkey". American Mineralogist. 87 (4): 405–416. doi:10.2138/am-2002-0404.
^Klein, Cornelis and Cornelius S. Hurlbut, Jr., Manual of Mineralogy, 1985, Wiley 20th ed., p. 380 ISBN0-471-80580-7
^. Archived from the original on 2010-06-10. Retrieved 2009-12-19. Delaware State Mineral, Sillimanite, Delaware Geological Survey
^Ihlen, Peter M. (2000). "Utilisation of sillimanite minerals, their geology, and potential occurrences in Norway – an overview" (PDF). Geological Survey of Norway Bulletin. 436: 113. Retrieved 14 March 2022.
February 07, 2024
sillimanite, fibrolite, aluminosilicate, mineral, with, chemical, formula, al2sio5, named, after, american, chemist, benjamin, silliman, 1779, 1864, first, described, 1824, occurrence, chester, connecticut, generalcategorynesosilicateformula, repeating, unit, . Sillimanite or fibrolite is an aluminosilicate mineral with the chemical formula Al2SiO5 Sillimanite is named after the American chemist Benjamin Silliman 1779 1864 It was first described in 1824 for an occurrence in Chester Connecticut 4 SillimaniteGeneralCategoryNesosilicateFormula repeating unit Al2SiO5IMA symbolSil 1 Strunz classification9 AF 05Dana classification52 02 02a 01Crystal systemOrthorhombicCrystal classDipyramidal mmm H M symbol 2 m 2 m 2 m Space groupPbnmUnit cella 7 47 A b 7 66 A c 5 75 A Z 4IdentificationColorColourless or white to grey also brown yellow yellow green grey green blue green blue colourless in thin sectionCrystal habitPrismatic crystals fibrous acicularCleavage 010 perfectFractureSplinteryTenacityToughMohs scale hardness7LusterVitreous to subadamantine silkyStreakWhiteDiaphaneityTransparent to translucentSpecific gravity3 24Optical propertiesBiaxial Refractive indexna 1 653 1 661 nb 1 654 1 670 ng 1 669 1 684Birefringenced 0 020 0 022PleochroismColourless to pale brown to yellow2V angle21 30 References 2 3 4 5 Kyanite Andalusite Sillimanite Phase diagram of Al2SiO5 aluminosilicates 6 Contents 1 Occurrence 2 Uses 3 Gallery 4 See also 5 ReferencesOccurrence editSillimanite or fibrolite is one of three aluminosilicate polymorphs the other two being andalusite and kyanite A common variety of sillimanite is known as fibrolite so named because the mineral appears like a bunch of fibres twisted together when viewed in thin section or even by the naked eye Both the fibrous and traditional forms of sillimanite are common in metamorphosed sedimentary rocks It is an index mineral indicating high temperature but variable pressure Example rocks include gneiss and granulite It occurs with andalusite kyanite potassium feldspar almandine cordierite biotite and quartz in schist gneiss hornfels and also rarely in pegmatites 3 Dumortierite and mullite are similar mineral species found in porcelain 7 Sillimanite has been found in Brandywine Springs New Castle County Delaware It was named by the State Legislature in 1977 as the state mineral of Delaware by the suggestion of the Delaware Mineralogical Society 8 Uses editNatural sillimanite is used in the manufacture of high alumina refractories or 55 60 alumina bricks However it has mostly been replaced by the other aluminosilicate polymorphs andalusite and kyanite for this purpose 9 As of 1998 update sillimanite was just 2 of all aluminosilicate mineral production in the western world 10 Gallery edit nbsp Silimanite crystal from Sri Lanka nbsp Fibrolite micrographSee also editList of minerals List of minerals named after peopleReferences edit Warr L N 2021 IMA CNMNC approved mineral symbols Mineralogical Magazine 85 3 291 320 Bibcode 2021MinM 85 291W doi 10 1180 mgm 2021 43 S2CID 235729616 WebMineral entry Retrieved 2009 12 19 a b http rruff geo arizona edu doclib hom sillimanite pdf Handbook of Mineralogy a b http www mindat org min 3662 html Mindat org MacKenzie W S Guilford C 1980 Atlas of rock forming minerals in thin section Essex Longman Scientific amp Technical p 10 ISBN 0 582 45591 X Whitney D L 2002 Coexisting andalusite kyanite and sillimanite Sequential formation of three Al2SiO5 polymorphs during progressive metamorphism near the triple point Sivrihisar Turkey American Mineralogist 87 4 405 416 doi 10 2138 am 2002 0404 Klein Cornelis and Cornelius S Hurlbut Jr Manual of Mineralogy 1985 Wiley 20th ed p 380 ISBN 0 471 80580 7 Delaware State Mineral Delaware Geological Survey Archived from the original on 2010 06 10 Retrieved 2009 12 19 Delaware State Mineral Sillimanite Delaware Geological Survey Gilchrist J D 1977 Alumino Silicate Refractories Fuels Furnaces and Refractories 258 272 doi 10 1016 B978 0 08 020430 7 50027 X ISBN 9780080204307 Ihlen Peter M 2000 Utilisation of sillimanite minerals their geology and potential occurrences in Norway an overview PDF Geological Survey of Norway Bulletin 436 113 Retrieved 14 March 2022 Retrieved from https en wikipedia org w index php title Sillimanite amp oldid 1198111824, wikipedia, wiki, book, books, library,
