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Cryptohalite

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About CryptohaliteHide

Formula:
(NH4)2[SiF6]
Colour:
Colourless, white, grey; colourless in transmitted light
Lustre:
Vitreous
Hardness:
Specific Gravity:
2.004
Crystal System:
Isometric
Name:
From the Greek κρυπτός, concealed, and άλς, salt, in allusion to its intimate mixture with salammoniac in the type locality occurrence.
Dimorph of:
Isostructural with:
This page provides mineralogical data about Cryptohalite.


Classification of CryptohaliteHide

Approved, 'Grandfathered' (first described prior to 1959)
3.CH.15

3 : HALIDES
C : Complex halides
H : Silicofluorides
11.5.1.2

11 : HALIDE COMPLEXES
5 : AmBX6
8.12.5

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

Physical Properties of CryptohaliteHide

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

Optical Data of CryptohaliteHide

Type:
Isotropic

Chemical Properties of CryptohaliteHide

Formula:
(NH4)2[SiF6]
IMA Formula:
(NH4)2SiF6

Crystallography of CryptohaliteHide

Crystal System:
Isometric
Class (H-M):
m3m (4/m 3 2/m) - Hexoctahedral
Space Group:
Fm3m
Cell Parameters:
a = 8.39 Å
Unit Cell 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.

Type Occurrence of CryptohaliteHide

Synonyms of CryptohaliteHide

Other Language Names for CryptohaliteHide

Related Minerals - Nickel-Strunz GroupingHide

3.CH.05MalladriteNa2[SiF6]Trig.
3.CH.10Bararite(NH4)2[SiF6]Trig. 3m (3 2/m)
3.CH.15HieratiteK2[SiF6]Iso. m3m (4/m 3 2/m) : Fm3m
3.CH.20DemartiniteK2[SiF6]Hex. 6mm : P63mc
3.CH.25KnasibfiteK3Na4[SiF6]3[BF4]Orth. mm2 : Imm2

Related Minerals - Dana Grouping (8th Ed.)Hide

11.5.1.1HieratiteK2[SiF6]Iso. m3m (4/m 3 2/m) : Fm3m
11.5.1.3Panichiite(NH4)2SnCl6Iso. m3m (4/m 3 2/m) : Fm3m

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

8.12.1FerrucciteNa[BF4]Orth.
8.12.2Avogadrite(K,Cs)[BF4]Orth. mmm (2/m 2/m 2/m) : Pnma
8.12.3MalladriteNa2[SiF6]Trig.
8.12.4HieratiteK2[SiF6]Iso. m3m (4/m 3 2/m) : Fm3m
8.12.6Bararite(NH4)2[SiF6]Trig. 3m (3 2/m)

Other InformationHide

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

References for CryptohaliteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
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 CryptohaliteHide

Localities for CryptohaliteHide

ⓘ - Click for further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
Czech Republic
 
  • 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; Witzke, T., de Wit, F., Kolitsch, U. and Blaß, G. (2015): Mineralogy of the Burning Anna I Coal Mine Dump, Alsdorf, Germany. Chapter 7, pp. 203-240, in: Stracher, G. B., Prakash, A. and Sokol, E. V.: Coal and Peat Fires: A Global Perspective, Volume 3: Case Studies - Coal Fires, Elsevier, 786 pp.
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 (TL)
 
  • 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.
Poland
 
  • Lower Silesia (Dolnośląskie)
    • Kłodzko District
      • Nowa Ruda (Neurode)
Fabiańska, M.J., Ciesielczuk, J., Kruszewski, Ł., Misz-Kennan, M., Blake, D.R., Stracher, G., Moszumańska, I., 2013: Gaseous compounds and efflorescences generated in self-heating coal-waste dumps — A case study from the Upper and Lower Silesian Coal Basins (Poland). International Journal of Coal Geology: 116-117: 247-261
  • Upper Silesia (Śląskie)
    • Upper Silesian Coal Basin
      • Rybnik Coal Area
        • Radlin
Łukasz Kruszewski (2012) Unique chloride assemblage of exhalative origin from burning coal-mining dump in Radlin (Rybnik Coal Area, S Poland). Mineralogical Society of Poland Special Papers 40
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.
Mineral and/or Locality  
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