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Cristobalite Mineral Data |
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Cristobalite Mineral Data |
General Cristobalite Information |
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 Chemical Formula: |
SiO2 | ||
| Composition: |
Molecular Weight = 60.08 gm | ||
| Silicon 46.74 % Si 100.00 % SiO2 | |||
| Oxygen 53.26 % O | |||
| ______ ______ | |||
| 100.00 % 100.00 % = TOTAL OXIDE | |||
| Empirical Formula: |
(SiO2) | ||
| Environment: |
Post-volcanic, magmatic, and secondary. | ||
| IMA Status: |
Valid Species (Pre-IMA) 1887 | ||
| Locality: |
Cerro San Cristobal, Mexico. Link to MinDat.org Location Data. | ||
| Name Origin: |
Named after its locality. | ||
| Name Pronunciation: |
Cristobalite + Pronunciation  |
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Cristobalite Image | |||
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Images:
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Cristobalite Crystallography |
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| Axial Ratios: |
a:c = 1:1.39167 | ||
| Cell Dimensions: |
a = 4.971, c = 6.918, Z = 4; V = 170.95 Den(Calc)= 2.33 | ||
| Crystal System: |
Tetragonal - Trapezohedral H-M Symbol (4 2 2) Space Group: P 41212 | ||
| X Ray Diffraction: |
By Intensity(I/Io): 4.05(1), 2.485(0.2), 2.841(0.13), | ||
Physical Properties of Cristobalite |
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| Cleavage: |
None | ||
| Color: |
Blue gray, Brown, Gray, Yellow, White. | ||
| Density: |
2.27 | ||
| Diaphaneity: |
Translucent to transparent | ||
| Fracture: |
Brittle - Generally displayed by glasses and most non-metallic minerals. | ||
| Habit: |
Crystalline - Fine - Occurs as well-formed fine sized crystals. | ||
| Habit: |
Spherical - Spherical, rounded aggregates. | ||
| Hardness: |
6.5 - Pyrite | ||
| Luminescence: |
Fluorescent, Short UV=green red, Long UV=reen red. | ||
| Luster: |
Vitreous (Glassy) | ||
| Magnetism: |
Nonmagnetic | ||
| Streak: |
white | ||
Optical Properties of Cristobalite |
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| Gladstone-Dale: |
CI meas= -0.03 (Excellent) - where the CI = (1-KPDmeas/KC) CI calc= -0.004 (Superior) - where the CI = (1-KPDcalc/KC) KPDcalc= 0.2088,KPDmeas= 0.2143,KC= 0.208 Ncalc = 1.47 - 1.48 |
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| Optical Data: |
Isotropic, n=1.485-1.487. | ||
Calculated Properties of Cristobalite |
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| Electron Density: |
Bulk Density (Electron Density)=2.33 gm/cc note: Specific Gravity of Cristobalite =2.33 gm/cc. |
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| Fermion Index: |
Fermion Index = 0.02 Boson Index = 0.98 |
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| Photoelectric: |
PECristobalite = 1.80 barns/electron U=PECristobalite x rElectron Density= 4.18 barns/cc. |
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| Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Cristobalite is Not Radioactive |
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Cristobalite Classification |
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| Dana Class: |
75.01.01.01 (75)Tectosilicate Si Tetrahedral Frameworks | ||
| (75.01)SiO2 with [4] coordinated Si | |||
| (75.01.01)Dana Group | |||
| Strunz Class: |
04.DA.15 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate | ||
| 04.D - Metal:Oxygen = 1:2 and similar | |||
| 04.DA -With small cations | |||
Other Cristobalite Information |
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| References: |
NAME( Duda&Rejl90) PHYS. PROP.(Collectors Book of Fluorescent Minerals) OPTIC PROP.(Heinrich65) | ||
| See Also: |
Links to other databases for Cristobalite : 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 - Glendale Community College 8 - Google Images 9 - Google Scholar 10 - Handbook of Mineralogy (MinSocAm) 11 - Handbook of Mineralogy (UofA) 12 - MinDAT 13 - Mineral and Gemstone Kingdom 14 - Mineralienatlas (Deutsch) 15 - Online Mineral Museum 16 - QUT Mineral Atlas 17 - Ruff.Info 18 - Scandinavian mineral gallery 19 - UCLA - Petrography Thin-Sections 20 - WWW-MINCRYST Search for Cristobalite using: Visit our Advertisers for Cristobalite : Ask about Cristobalite here : Print or Cut-and-Paste your Cristobalite Specimen Label here :
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