General Coesite InformationSiO2 |
Molecular Weight = 60.08 gm |
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Silicon 46.74 % Si 100.00 % SiO2 |
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Oxygen 53.26 % O |
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100.00 % 100.00 % = TOTAL OXIDE |
(SiO2) |
High temperature and high pressure polymorph of quartz (500-800 deg C, ~ 30-35 kbar). Formed in impact craters and ultra-high-pressure eclogite rocks. |
Valid Species (Pre-IMA) 1954 |
Metor Crater, Cononino County, Arizona, USA. Link to MinDat.org Location Data. |
Named for Loring Coes, Jr. (1915-1973), American chemist, Norton Company, who first synthesized the phase. |
ICSD 18112 |
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PDF 14-654 |
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Coesite Crystallographya:b:c =0.5791:1:0.5791 |
a = 7.17, b = 12.38, c = 7.17, Z = 16; beta = 120° V = 551.18 Den(Calc)= 2.90 |
Monoclinic - PrismaticH-M Symbol (2/m) Space Group: C 2/c |
By Intensity(I/Io): 3.098(1), 3.432(0.5), 2.77(0.15), |
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| Physical Properties of CoesiteNone |
Colorless. |
2.93 |
Transparent |
Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz). |
Inclusions - Generally found as inclusions in other minerals. |
7.5 - Garnet |
Vitreous (Glassy) |
white |
| Optical Properties of CoesiteCI meas= 0.022 (Excellent) - where the CI = (1-KPDmeas/KC) |
CI calc= 0.012 (Superior) - where the CI = (1-KPDcalc/KC) KPDcalc= 0.2055,KPDmeas= 0.2034,KC= 0.208 Ncalc = 1.6 - 1.61 Biaxial (+), a=1.593-1.594, b=1.595, g=1.599, bire=0.0050-0.0060, 2V(Calc)=54-72, 2V(Meas)=54-64. Dispersion r < v weak. |
| Calculated Properties of CoesiteBulk Density (Electron Density)=2.90 gm/cc |
note: Specific Gravity of Coesite =2.90 gm/cc. Fermion Index = 0.02 |
Boson Index = 0.98 PECoesite = 1.80 barns/electron |
U=PECoesite x rElectron Density= 5.20 barns/cc. GRapi = 0 (Gamma Ray American Petroleum Institute Units) |
Coesite is Not Radioactive | Coesite Classification75.01.04.01 (75)Tectosilicate Si Tetrahedral Frameworks |
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(75.01)SiO2 with [4] coordinated Si |
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(75.01.04)Dana Group |
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04.DA.35 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate |
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04.D - Metal:Oxygen = 1:2 and similar |
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04.DA -With small cations |
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| Other Coesite InformationNAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Dana8) |
Links to other databases for Coesite : |
1 - Am. Min. Crystal Structure Database 2 - Amethyst Galleries' Mineral Gallery 3 - Athena 4 - EUROmin Project 5 - Ecole des Mines de Paris 6 - GeoScienceWorld 7 - Google Images 8 - Google Scholar 9 - Handbook of Mineralogy (MinSocAm) 10 - Handbook of Mineralogy (UofA) 11 - MinDAT 12 - Mineral and Gemstone Kingdom 13 - Mineralienatlas (Deutsch) 14 - Minerals in Thin Section-University of North Carolina 15 - Online Mineral Museum 16 - QUT Mineral Atlas 17 - Ruff.Info 18 - WWW-MINCRYST Search for Coesite using: Visit our Advertisers for Coesite : B and L Fine MineralsDakota Matrix Minerals Dan & Diana Weinrich Mineral Auctions Excalibur Mineral Corp. Exceptional Minerals John Betts Fine Minerals Mineral News Mineral of the Month Club NY/NJ Gem & Mineral Show TIMA Mineral Analyzer Weinrich Minerals, Inc. Wright's Rock Shop Ask about Coesite here : Print or Cut-and-Paste your Coesite Specimen Label here :
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