General Coesite Information Chemical Formula: |
SiO2 |
Composition: |
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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______ ______ |
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100.00 % 100.00 % = TOTAL OXIDE |
Empirical Formula: |
(SiO2) |
Environment: |
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. |
IMA Status: |
Valid Species (Pre-IMA) 1954 |
Locality: |
Metor Crater, Cononino County, Arizona, USA. Link to MinDat.org Location Data. |
Name Origin: |
Named for Loring Coes, Jr. (1915-1973), American chemist, Norton Company, who first synthesized the phase. |
Synonym: |
ICSD 18112 |
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PDF 14-654 |
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Images:
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Coesite Crystallography Axial Ratios: |
a:b:c =0.5791:1:0.5791 |
Cell Dimensions: |
a = 7.17, b = 12.38, c = 7.17, Z = 16; beta = 120° V = 551.18 Den(Calc)= 2.90 |
Crystal System: |
Monoclinic - PrismaticH-M Symbol (2/m) Space Group: C 2/c |
X Ray Diffraction: |
By Intensity(I/Io): 3.098(1), 3.432(0.5), 2.77(0.15), |
Crystal Structure:
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Mouse
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| Physical Properties of Coesite Cleavage: |
None |
Color: |
Colorless. |
Density: |
2.93 |
Diaphaneity: |
Transparent |
Fracture: |
Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz). |
Habit: |
Inclusions - Generally found as inclusions in other minerals. |
Hardness: |
7.5 - Garnet |
Luster: |
Vitreous (Glassy) |
Streak: |
white |
| Optical Properties of Coesite Gladstone-Dale: |
CI 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 Optical Data: |
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 Coesite Electron Density: |
Bulk Density (Electron Density)=2.90 gm/cc |
note: Specific Gravity of Coesite =2.90 gm/cc. Fermion Index: |
Fermion Index = 0.02 |
Boson Index = 0.98 Photoelectric: |
PECoesite = 1.80 barns/electron |
U=PECoesite x rElectron Density= 5.20 barns/cc. Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units) |
Coesite is Not Radioactive | Coesite Classification Dana Class: |
75.01.04.01 (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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Strunz Class: |
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 Information References: |
NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Dana8) |
See Also: |
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 : A Bijoux Google Search for CoesiteAdam's Minerals Google Search for Coesite Cape Minerals Google Search for Coesite Dakota Matrix Minerals Google Search for Coesite Excalibur Mineral Corp. Google Search for Coesite Exceptional Minerals Google Search for Coesite John Betts Fine Minerals Search for Coesite McDougall Minerals Google Search for Coesite Mineral News Website Link Rock and Mineral Shows Google Search for Coesite Weinrich Minerals, Inc. Google Search for Coesite Ask about Coesite here : Print or Cut-and-Paste your Coesite Specimen Label here :
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