8.12.5

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

Mineral SymbolsHide

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Symbol	Source	Reference for Standard
Cphl	IMA–CNMNC	Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43

Physical Properties of CryptohaliteHide

Lustre:

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

Chemistry of CryptohaliteHide

Mindat Formula:

(NH₄)₂[SiF₆]

Element Weights:

Element	% weight
F	63.985 %
Si	15.765 %
N	15.724 %
H	4.526 %

Calculated from ideal end-member formula.

Elements listed:

F, H, N, Si - search for minerals with similar chemistry

Crystallography of CryptohaliteHide

Crystal System:

Isometric

Class (H-M):

m3m(4/m32/m) - Hexoctahedral

Space Group:

Fm3m

Cell Parameters:

a = 8.39 Å

Unit Cell V:

590.59 Å³ (Calculated from Unit Cell)

Morphology:

Artificial crystals are cubo-octahedral and octahedral. Massive, as lumps with a mammillary surface or crusts; arborescent.

Crystal StructureHide

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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure

ID	Species	Reference	Link	Year	Locality	Pressure (GPa)	Temp (K)
0012983	Cryptohalite	Schlemper E O, Hamilton W C, Rush J J (1966) Structure of cubic ammonium fluosilicate: Neutron-diffraction and neutron-inelastic-scattering studies Journal of Chemical Physics 44 2499-2505		1966	synthetic	0	293
0017907	Cryptohalite	Bozorth R (1922) The Crystal Structure of Ammonium Fluosilicate _cod_database_code 1010992 Journal of the American Chemical Society 44 1066-1070		1922		0	293

CIF Raw Data - click here to close

data_global
_chemical_name_mineral 'Cryptohalite'
loop_
_publ_author_name
'Schlemper E O'
'Hamilton W C'
'Rush J J'
_journal_name_full 'Journal of Chemical Physics'
_journal_volume 44 
_journal_year 1966
_journal_page_first 2499
_journal_page_last 2505
_publ_section_title
;
 Structure of cubic ammonium fluosilicate: Neutron-diffraction and
 neutron-inelastic-scattering studies
;
_database_code_amcsd 0012983
_chemical_compound_source 'Synthetic'
_chemical_formula_sum 'Si N2 F6 H8'
_cell_length_a 8.395
_cell_length_b 8.395
_cell_length_c 8.395
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 591.646
_exptl_crystal_density_diffrn      2.000
_symmetry_space_group_name_H-M 'F m 3 m'
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loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
Si   0.00000   0.00000   0.00000   1.00000
N   0.25000   0.25000   0.25000   1.00000
F   0.20110   0.00000   0.00000   1.00000
H   0.16800   0.16800   0.26900   0.33333
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_23
Si 0.02149 0.02149 0.02149 0.00000 0.00000 0.00000
N 0.02781 0.02781 0.02781 0.00000 0.00000 0.00000
F 0.02024 0.03424 0.03424 0.00000 0.00000 0.00000
H 0.06212 0.06212 0.11996 -0.02713 -0.01071 -0.01071

X-Ray Powder DiffractionHide

Powder Diffraction Data:

d-spacing	Intensity
4.844 Å	(100)
2.422 Å	(45)
2.098 Å	(35)
4.195 Å	(25)
2.967 Å	(18)
1.615 Å	(18)
2.531 Å	(8)

Comments:

Synthetic.

Geological EnvironmentHide

Paragenetic Mode(s):

Paragenetic Mode	Earliest Age (Ga)
Stage 7: Great Oxidation Event	<2.4
45b : [Other oxidized fumarolic minerals]
Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere	<0.6
50 : Coal and/or oil shale minerals	<0.36
Stage 10b: Anthropogenic minerals	<10 Ka
54 : Coal and other mine fire minerals (see also #51 and #56)

Type Occurrence of CryptohaliteHide

Type Locality:

ⓘ Mount Vesuvius, Metropolitan City of Naples, Campania, Italy

Place of Conservation of Type Material:

No defined type material.

Associated Minerals at Type Locality:

Bararite

Salammoniac

Synonyms of CryptohaliteHide

Criptoalite (in part)

Other Language Names for CryptohaliteHide

Dutch:Cryptohaliet

German:Kryptohalit

Russian:Криптогалит

Common AssociatesHide

Associations Based on Photo Data:

4 photos of Cryptohalite associated with Bararite	(NH₄)₂[SiF₆]
3 photos of Cryptohalite associated with Native Sulphur	S₈
1 photo of Cryptohalite associated with 'Humic coal series'

Related Minerals - Strunz-mindat Grouping Hide

3.CH.05	Malladrite	Na₂[SiF₆]	Trig. 32 : P321
3.CH.10	Bararite	(NH₄)₂[SiF₆]	Trig. 3m(32/m)
3.CH.15	Hieratite	K₂[SiF₆]	Iso. m3m(4/m32/m) : Fm3m
3.CH.20	Demartinite	K₂[SiF₆]	Hex. 6mm : P6₃mc
3.CH.25	Knasibfite	K₃Na₄[SiF₆]₃[BF₄]	Orth. mm2 : Imm2
3.CH.30	Heklaite	KNaSiF₆	Orth. mmm(2/m2/m2/m) : Pnma

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.

Internet Links for CryptohaliteHide

mindat.org URL:

https://www.mindat.org/min-1163.html
Please feel free to link to this page.

Search Engines:

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Look for Cryptohalite in the Rock H. Currier Digital Library

External Links:

Look for Cryptohalite on Webmineral

Look for Cryptohalite on Wikipedia

Look for Cryptohalite on Mineralien Atlas

Raman and XRD data at RRUFF project

References and PDF downloads at RRUFF project

American Mineralogist Crystal Structure Database

Handbook of Mineralogy page PDF

Mineral Dealers:

Buy from D. Joyce minerals

References for CryptohaliteHide

Reference List:

Scacchi, A. (1873) Contribuzioni mineralogiche per servire alla storia dell’ incendio Vesuviano del Mese di Aprile, 1872. Part 2. Reale Accademia delle Scienze Fisische e Matematiche (Naples): 1–69. (as Criptoalite).

Topsøe, H., Christiansen, C. (1874) Recherches optique sur quelques series de substances isomorphes. Annales de chimie et de physique, Paris: 1: 5-99 (22-23).

Gossner, B. (1903) Ammoniumsiliciumfluorid. Zeitschrift für Kristallographie, Mineralogie und Petrographie, Leipzig: 38: 147-148.

Bozorth, R.M. (1922) The crystal structure of ammonium fluosilicate. Journal of the American Chemical Society: 44(5): 1066-1070.

Christie, W.A.K. (1926) An Occurrence of Cryptohalite (Ammonium Fluosilicate). Records of the Geological Survey of India, Calcutta: 59: 233.

Ketelaar, J. A. A. (1935) Die Kristallstruktur von K-, Rb-, Cs- und Tl-Silicofluorid und von LiMnO4.3H2O. Zeitschrift für Kristallographie - Crystalline Materials, 92 (1) 155-156 doi:10.1524/zkri.1935.92.1.155

Palache, Charles; Berman, Harry; Frondel, Clifford (1951) The System of Mineralogy (7th ed.) Vol. 2 - Halides, Nitrates, Borates, Carbonates, Sulfates, Phosphates, Arsenates, Tungstates, Molybdates, Etc. John Wiley and Sons.pp.104-105

Schlemper, Elmer O., Hamilton, Walter C., Rush, J. J. (1966) Structure of Cubic Ammonium Fluosilicate: Neutron‐Diffraction and Neutron‐Inelastic‐Scattering Studies. The Journal of Chemical Physics, 44 (6) 2499-2505 doi:10.1063/1.1727071

Jenkins, T E (1986) Anharmonic interactions in solids: a Raman investigation of some vibrational states in ammonium fluorosilicate. Journal of Physics C: Solid State Physics, 19 (7). 1065-1070 doi:10.1088/0022-3719/19/7/017

Rehim, A.M. (1992) Thermal study of synthesis of cryptohalite. Journal of thermal analysis, 38(3), 475-486.

(2005) Cryptohalite. Handbook of Mineralogy. Mineralogical Society of America

Localities for CryptohaliteHide

Showing 19 localities.

This 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.

Hide all sections | Show all sections

Locality ListHide

- This locality has map coordinates listed.

- This locality has estimated coordinates. ⓘ - Click for references and 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 (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.


Czech Republic
Central Bohemian Region ⓘ Kladno District	Žáček et al. (1995)
ⓘ Libušin	Palache et al. (1951)
ⓘ Kladno mine	David Parfitt collection
Hradec Králové Region Trutnov District Lampertice ⓘ Jan Šverma Mine	Harapát
Radvanice ⓘ Kateřina Coal Mine	Žáček et al. (1998)
Moravian-Silesian Region Ostrava-City District Ostrava Heřmanice ⓘ Heřmanice dump	Matýsek et al. (2022)

Germany
Baden-Württemberg Freiburg Region Ortenaukreis Oberwolfach ⓘ Clara Mine	Walenta (1992)
North Rhine-Westphalia Cologne Aachen Alsdorf ⓘ Anna mine	XRD and EDX-analysed by Günter Blaß +1 other reference

Iceland
Southern Region Vestmannaeyjar Vestmannaeyjar archipelago (Westman islands) Heimaey Island ⓘ Eldfell Volcano	Balić-Žunić et al. (2016)

India
Jharkhand Dhanbad District Jharia Coalfield ⓘ Barari Colliery	Palache et al. (1951)

Italy (TL)
Campania Metropolitan City of Naples ⓘ Mount Vesuvius (TL)	Palache et al. (1951) +1 other reference
ⓘ Vesuvius fumaroles	Pelloux (1927) +2 other references

Poland
Lower Silesian Voivodeship Kłodzko County Nowa Ruda Piast Mine ⓘ Piast mine heap	Fabiańska et al. (2013)
Silesian Voivodeship Wodzisław County Radlin ⓘ Marcel mine heap	Kruszewski (2012)

Saint Helena， Ascension and Tristan da Cunha
ⓘ Tristan da Cunha Archipelago	Bailey (1980)

Tajikistan
Sughd Ayni District Fan-Jagnob coal deposit ⓘ Kukhi-Malik tract	PXRD

USA
Pennsylvania Columbia County ⓘ Centralia
Northumberland County ⓘ Burnside	Lapham et al. (1980)
Schuylkill County Shenandoah ⓘ Kehley's Run Mine	Finkelman et al. (1974) +1 other reference

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Cryptohalite

About CryptohaliteHide

Unique IdentifiersHide

IMA Classification of CryptohaliteHide

Classification of CryptohaliteHide