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Cryptohalite

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Formula:
(NH
 
4
)
 
2
[SiF
 
6
]
System:IsometricColour:Colourless, white, grey; ...
Lustre:VitreousHardness:
Name:From the Greek κρυπτός, concealed, and άλς, salt, in allusion to its intimate mixture with salammoniac in the type locality occurrence.
Dimorph of:Bararite
Isostructural with:Hieratite
This page provides mineralogical data about Cryptohalite.

Classification of Cryptohalite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:3/B.02-30
Nickel-Strunz 10th (pending) edition ID:3.CH.15

3 : HALIDES
C : Complex halides
H : Silicofluorides
Dana 8th edition ID:11.5.1.2

11 : HALIDE COMPLEXES
5 : AmBX6
Hey's CIM Ref.:8.12.5

8 : Halides - Fluorides, Chlorides, Bromides and Iodides; also Fluoborates and Fluosilicates
12 : Fluorborates (BF'4) and fluosilicates (SiF''6)
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Type Occurrence of Cryptohalite

Type Locality:Mt Vesuvius, Somma-Vesuvius Complex, Naples Province, Campania, Italy
Year of Discovery:1873
Associated Minerals at type locality:
SalammoniacBararite

Physical Properties of Cryptohalite

Lustre:Vitreous
Colour:Colourless, white, grey; colourless in transmitted light
Hardness (Mohs):
Cleavage:Perfect
on {111}
Density (measured):2.004 g/cm3
Density (calculated):2.029 g/cm3

Crystallography of Cryptohalite

Crystal System:Isometric
Class (H-M):m3m (4/m 3 2/m) - Hexoctahedral
Space Group:Fm3m
Cell Parameters:a = 8.39Å
Unit Cell Volume:V 590.59 ų (Calculated from Unit Cell)
Morphology:Artificial crystals are cubo-octahedral and octahedral. Massive, as lumps with a mammillary surface or crusts; arborescent.

Optical Data of Cryptohalite

Type:Isotropic

Chemical Properties of Cryptohalite

Formula:
(NH
 
4
)
 
2
[SiF
 
6
]
Simplified for copy/paste:(NH4)2[SiF6]
Essential elements:F, H, N, Si
All elements listed in formula:F, H, N, Si

Relationship of Cryptohalite to other Species

Related Minerals - Nickel-Strunz Grouping):

- +
3.CH.05Malladrite
Na
 
2
[SiF
 
6
]
3.CH.10Bararite
(NH
 
4
)
 
2
[SiF
 
6
]
3.CH.15Hieratite
K
 
2
[SiF
 
6
]
3.CH.20Demartinite
K
 
2
[SiF
 
6
]
3.CH.25Knasibfite
K
 
3
Na
 
4
[SiF
 
6
]
 
3
[BF
 
4
]
Related Minerals - Hey's Index Grouping:

- +
8.12.1Ferruccite
Na[BF
 
4
]
8.12.2Avogadrite
(K,Cs)[BF
 
4
]
8.12.3Malladrite
Na
 
2
[SiF
 
6
]
8.12.4Hieratite
K
 
2
[SiF
 
6
]
8.12.6Bararite
(NH
 
4
)
 
2
[SiF
 
6
]

Other Names for Cryptohalite

Synonyms:
Criptoalite
Other Languages:
German:Kryptohalit
Russian:Криптогалит

Other Information

Other Information:Soluble in cold water, more so in hot water.
Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Cryptohalite

Reference List:

- +
Scacchi (1873) Reale accademia delle scienze fisische e matematiche, Naples, Att,: 6, no. 9 (as Criptoalite).

Topsøe (1874) Annales de chimie et de physique, Paris: 1: 22.

Gossner (1903) Zeitschrift für Kristallographie, Mineralogie und Petrographie, Leipzig: 38: 147.

Bozorth (1922) American Chemical Society Journal: 44: 1066.

Christie (1926) Rec. Geol. Survey India: 59: 233.

Ketelaar (1935) Zeitschrift für Kristallographie, Mineralogie und Petrographie, Leipzig: 92: 155.

Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: Halides, Nitrates, Borates, Carbonates, Sulfates, Phosphates, Arsenates, Tungstates, Molybdates, Etc. John Wiley and Sons, Inc., New York, 7th edition, revised and enlarged: 104-105.

Journal of Chemical Physics: 44: 2499-2505.

Internet Links for Cryptohalite

Search Engines:
  • Look for Cryptohalite on Google
  • Look for Cryptohalite images on Google
  • External Links:
  • Look for Cryptohalite on Webmineral
  • Look for Cryptohalite on Athena Mineralogy
  • Look for Cryptohalite on Wikipedia
  • Look for Cryptohalite on Mineralien Atlas
  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Cryptohalite details from Handbook of Mineralogy (PDF)
  • Mineral Dealers:
  • Buy from McDougall Minerals
  • Cryptohalite specimens for sale - minfind.com
  • Find Cryptohalite on www.crystalclassics.co.uk
  • Buy rare minerals from Excalibur Minerals
  • The Arkenstone - Fine Minerals
  • Buy minerals from YourMineralCollection
  • Buy RARE Minerals from Rocks of Africa
  • Search for Cryptohalite on Well-Arranged Molecules
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  • Top quality minerals from Kristalle of California
  • Fine minerals from bisbeeborn.com
  • Localities for Cryptohalite

    The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    Czech Republic
     
    • Bohemia (Böhmen; Boehmen)
      • Central Bohemia Region
    Zacek, V., Oplustil, S., Mayova, A. & Meyer, F. R. (1995): Die Mineralien von Kladno in Mittelböhmen, Tschechische Republik. Mineralien-Welt 6 (1), 13-30 (in German).
    Palache, Charles, Harry Berman & Clifford Frondel (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana Yale University 1837-1892, Volume 2: 105.
    David Parfitt collection
      • Hradec Králové Region
        • Trutnov (Trautenau)
          • Radvanice
    Žáček, V., Ondruš, P.: Mineralogy of recently formed sublimates from Kateřina colliery in Radvanice, Eastern Bohemia, Czech Republic. Bulletin of the Czech geological survey, 1998, vol. 73, no. 2, s. 289-302.
          • Žacléř
    Harapát, L.: Minerály hořících hald dolu Jan Šverma u Žacléře. Časopis pro mineralogii a geologii, 1986, roč. 31, č. 1, s. 99-100.
    Germany
     
    • Baden-Württemberg
      • Black Forest
        • Wolfach
          • Oberwolfach
            • Rankach valley
    Walenta, K. (1992): Die Mineralien des Schwarzwaldes. Chr. Weise Verlag, München, 336 pp. (in German)
    • North Rhine-Westphalia
      • Aachen
        • Alsdorf
    XRD and EDX-analysed by Günter Blaß
    India
     
    • Bihar
      • Jharia Coalfield
    Palache, Charles, Harry Berman & Clifford Frondel (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana Yale University 1837-1892, Volume 2: 105.
    Italy
     
    • Campania
      • Naples Province
        • Somma-Vesuvius Complex
    Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 105; Lapis (1994): 5: 13-23, 58.
    Saint Helena
     
    Bailey, J. C: Formation of cryolite and other aluminofluorides: A petrologic review. Bull. geol. Soc. Denmark, vol. 29, pp. 1-45. Copenhagen, June 10th, 1980
    Tajikistan
     
    • Viloyati Sogd (Viloyati Sughd; Viloyati Khodzhent; Viloyati Leninabad)
      • Zeravshan Range
        • Yagnob River
    PXRD
    USA
     
    • Pennsylvania
      • Columbia Co.
      • Schuylkill Co.
        • Shenandoah
    Reed, Juliet C. (1976), Annotated Biblio. of Minerals New to the Pennsylvania List 1965-1974, The Mineralogical Society of PA, Inc.: 29-30; Finkelman, et al, Geol. Soc. Am. Abstracts with Programs, Vol. 5(1): 27-28.
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    Copyright © Jolyon Ralph and Ida Chau 1993-2014. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them. Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of thousands of members and supporters. Mindat does not offer minerals for sale. If you would like to add information to improve the quality of our database, then click here to register.
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