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Cryptohalite Mineral Data
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General Cryptohalite Information
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Chemical Formula: |
(NH4)2SiF6 |
Composition: |
Molecular Weight = 178.15 gm |
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Silicon 15.76 % Si 33.73 % SiO2 |
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Hydrogen 4.53 % H - % Calc as (NH4)2O |
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Nitrogen 15.72 % N 29.23 % (NH4)2O |
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Fluorine 63.98 % F 63.98 % F |
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- %
F -26.94 % -O=F2 |
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______ ______ |
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100.00 % 100.00 % = TOTAL OXIDE |
Empirical Formula: |
(NH4)2SiF6 |
Environment: |
Volcanic sublimate. Dimorphous with bararite, the lower-temperature form. |
IMA Status: |
Valid Species (Pre-IMA) 1873 |
Locality: |
Vesuvius, Campania, Italy. Link to MinDat.org Location Data. |
Name Origin: |
Named from the Greek for concealed and salt, for being admixed with sal ammoniac. |
Synonym: |
ICSD 18033 |
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PDF 44-1484 |
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Cryptohalite Image |
Images:
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Cryptohalite
Comments: White to colorless crystals of cryptohalite. The red color is due to admixtured (amorphous ?) selenium.
Location: Kladno, Stredoceský Kraj, Bohemia, Czech Republic.
Scale: Picture size 5 mm.
© Thomas Witzke / Abraxas-Verlag |
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Images:
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Cryptohalite Crystallography
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Cell Dimensions: |
a = 8.395, Z = 4; V = 591.65 Den(Calc)= 2.00 |
Crystal System: |
Isometric - Hexoctahedral H-M Symbol (4/m 3 2/m) Space Group: F m3m |
X Ray Diffraction: |
By Intensity(I/Io): 4.844(1), 2.422(0.45), 2.098(0.35), |
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Physical Properties of Cryptohalite
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Cleavage: |
{111} Perfect |
Color: |
Colorless, Gray, White. |
Density: |
2.011 |
Diaphaneity: |
Transparent |
Hardness: |
2.5 - Finger Nail |
Luster: |
Vitreous (Glassy) |
Streak: |
white |
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Optical Properties of Cryptohalite
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Optical Data: |
Isotropic, n=1.369. |
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Calculated Properties of Cryptohalite
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Electron Density: |
Bulk Density (Electron Density)=2.02 gm/cc note: Specific Gravity of Cryptohalite =2.00 gm/cc. |
Fermion Index: |
Fermion Index = 0.16 Boson Index = 0.84 |
Photoelectric: |
PECryptohalite = 0.97 barns/electron U=PECryptohalite x rElectron Density= 1.96 barns/cc. |
Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Cryptohalite is Not Radioactive |
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Cryptohalite Classification
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Dana Class: |
11.05.01.02 (11)Halide Complexes; Alumino-fluorides |
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(11.05)where (A)m B (X)6 |
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(11.05.01)Dana Group |
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11.05.01.01 Hieratite K2SiF6 F m3m 4/m 3 2/m |
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11.05.01.02 Cryptohalite (NH4)2SiF6 F m3m 4/m 3 2/m |
Strunz Class: |
03.CH.15 03 - HALIDES |
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03.C - Complex Halides |
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03.CH - |
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03.CH.15 Cryptohalite (NH4)2SiF6 F m3m 4/m 3 2/m |
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03.CH.15 Hieratite K2SiF6 F m3m 4/m 3 2/m |
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Other Cryptohalite Information
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References: |
NAME( AntBidBlaNic3) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990) |
See Also: |
Links to other databases for Cryptohalite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
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Print or Cut-and-Paste your Cryptohalite Specimen Label here :
Cryptohalite
(NH4)2SiF6
Dana No: 11.05.01.02 Strunz No: 03.CH.15
Locality:
Notes:
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