Log InRegister
Quick Links : The Mindat ManualThe Rock H. Currier Digital LibraryMindat Newsletter [Free Download]
Home PageAbout MindatThe Mindat ManualHistory of MindatCopyright StatusWho We AreContact UsAdvertise on Mindat
Donate to MindatCorporate SponsorshipSponsor a PageSponsored PagesMindat AdvertisersAdvertise on Mindat
Learning CenterWhat is a mineral?The most common minerals on earthInformation for EducatorsMindat ArticlesThe ElementsThe Rock H. Currier Digital LibraryGeologic Time
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
Keyword(s):
 
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
Mining CompaniesStatisticsUsersMineral MuseumsClubs & OrganizationsMineral Shows & EventsThe Mindat DirectoryDevice SettingsThe Mineral Quiz
Photo SearchPhoto GalleriesSearch by ColorNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day GalleryPhotography

Cryolite

A valid IMA mineral species - grandfathered
This page is currently not sponsored. Click here to sponsor this page.
Hide all sections | Show all sections

About CryoliteHide

Formula:
Na2NaAlF6
Colour:
Colourless, white, brown, grey, black; colourless in transmitted light.
Lustre:
Vitreous, Greasy, Pearly
Hardness:
3 - 3½
Specific Gravity:
2.96 - 2.98
Crystal System:
Monoclinic
Name:
From the Greek κρύος, frost, and λίθος, stone, meaning "ice-stone" in allusion to its appearance.
A curiosity mineral. Colourless samples of this sodium-aluminium-fluoride mineral seemingly disappear in water due to the proximity of their refractive indices.

Historically, cryolite was used as an aluminium ore and later in the electrolytic processing of the aluminium ore bauxite.




Unique IdentifiersHide

Mindat ID:
1161
Long-form identifier:
mindat:1:1:1161:3
GUID
(UUID V4):
2aad8b81-c8be-490e-86f0-f03110dae967

IMA Classification of CryoliteHide

Approved, 'Grandfathered' (first described prior to 1959)
First published:
1799

Classification of CryoliteHide

3.CB.15

3 : HALIDES
C : Complex halides
B : Neso-aluminofluorides
11.6.1.1

11 : HALIDE COMPLEXES
6 : Aluminofluorides - Isolated Octahedra
8.6.5

8 : Halides - Fluorides, Chlorides, Bromides and Iodides; also Fluoborates and Fluosilicates
6 : Halides of Al

Mineral SymbolsHide

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

Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.

SymbolSourceReference
CrlIMA–CNMNCWarr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43
CrlWhitney & Evans (2010)Whitney, D.L. and Evans, B.W. (2010) Abbreviations for names of rock-forming minerals. American Mineralogist, 95, 185–187 doi:10.2138/am.2010.3371
CryThe Canadian Mineralogist (2019)The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download

Physical Properties of CryoliteHide

Vitreous, Greasy, Pearly
Transparency:
Transparent, Translucent
Comment:
Pearly on {001}
Colour:
Colourless, white, brown, grey, black; colourless in transmitted light.
Streak:
White
Hardness:
3 - 3½ on Mohs scale
Hardness:
VHN50=286 - 412 kg/mm2 - Vickers
Comment:
Normally published values of Mohs 2.5-3 are for massive material; crystals are harder. Vickers values are for (100). A full discussion is given in Pauly (1985).
Tenacity:
Brittle
Cleavage:
None Observed
Parting:
On {001} and {110}, producing cuboidal forms.
Fracture:
Irregular/Uneven
Density:
2.96 - 2.98 g/cm3 (Measured)    2.973(2) g/cm3 (Calculated)

Optical Data of CryoliteHide

Type:
Biaxial (+)
RI values:
nα = 1.339 - 1.339 nβ = 1.339 - 1.339 nγ = 1.340 - 1.340
2V:
Measured: 43°
Max Birefringence:
δ = 0.001
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
Moderate
Dispersion:
r < v
Optical Extinction:
X = b; Z ∧ c = −44°.

Chemistry of CryoliteHide

Mindat Formula:
Na2NaAlF6
Common Impurities:
Fe,Ca

Crystallography of CryoliteHide

Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Cell Parameters:
a = 7.7564(3) Å, b = 5.5959(2) Å, c = 5.4024(2) Å
β = 90.18°
Ratio:
a:b:c = 1.386 : 1 : 0.965
Unit Cell V:
234.48 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Crystals usually cuboidal with c, , or modified by r, v, k; also short prismatic [001]. {110} faces striated [111], [111], or [110]. Massive, coarsely granular.
Twinning:
Very common. Often repeated or polysynthetic with simultaneous occurrence of several twin laws, and reflecting the pseudo-orthorhombic symmetry of the unit cell.

1. By a 90° or 270° rotation on [110], penetration, common.

2. By a 180° rotation on [110], rhombic section (110), repeated, less common.

3. By a 120° rotation on [021], composition surface irregular; common, especially in granular material, as fine lamellae and probably always secondary.

4. By a 180° rotation on [111], rhombic section near (110), repeated; rare (not in granular material).

5. On (001) or by a 180° rotation on [100], composition plane (001).

6. On (100) or by a 180° rotation on [001], composition plane (100).

7. On (112), composition plane (112).

8. On (112), composition plane (112).

9. On (110), composition plane (110).

10. By a 180° rotation on [111], rhombic section near (110).

11. On (211).

(Palache et al (1951), Dana's System of Mineralogy, 7th. ed., vol. 2: 111).
Comment:
Spacegroup: P21/n (Mitchell et al. 2016); at 5K, the structure is the same as that at RT

Crystallographic forms of CryoliteHide

Crystal Atlas:
Image Loading
Click on an icon to view
Cryolite no.15 - Goldschmidt (1913-1926)
Cryolite no.16 - Goldschmidt (1913-1926)
3d models and HTML5 code kindly provided by www.smorf.nl.

Toggle
Edge Lines | Miller Indices | Axes

Transparency
Opaque | Translucent | Transparent

View
Along a-axis | Along b-axis | Along c-axis | Start rotation | Stop rotation

Crystal StructureHide

Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
View
CIF File    Best | x | y | z | a | b | c
Rotation
Stop | Start
Labels
Console Off | On | Grey | Yellow
IDSpeciesReferenceLinkYearLocalityPressure (GPa)Temp (K)
0005118CryoliteHawthorne F C, Ferguson R B (1975) Refinement of the crystal structure of cryolite The Canadian Mineralogist 13 377-38219750293
0007739CryoliteYang H, Ghose S, Hatch D M (1993) Ferroelastic phase transition in cryolite, Na3AlF6, a mixed fluoride perovskite: high temperature single crystal X-ray diffraction study and symmetry analysis of the transition mechanism Physics and Chemistry of Minerals 19 528-54419930293
0007740CryoliteYang H, Ghose S, Hatch D M (1993) Ferroelastic phase transition in cryolite, Na3AlF6, a mixed fluoride perovskite: high temperature single crystal X-ray diffraction study and symmetry analysis of the transition mechanism Physics and Chemistry of Minerals 19 528-54419930293
0007741CryoliteYang H, Ghose S, Hatch D M (1993) Ferroelastic phase transition in cryolite, Na3AlF6, a mixed fluoride perovskite: high temperature single crystal X-ray diffraction study and symmetry analysis of the transition mechanism Physics and Chemistry of Minerals 19 528-54419930293
0007742CryoliteYang H, Ghose S, Hatch D M (1993) Ferroelastic phase transition in cryolite, Na3AlF6, a mixed fluoride perovskite: high temperature single crystal X-ray diffraction study and symmetry analysis of the transition mechanism Physics and Chemistry of Minerals 19 528-54419930293
0007743CryoliteYang H, Ghose S, Hatch D M (1993) Ferroelastic phase transition in cryolite, Na3AlF6, a mixed fluoride perovskite: high temperature single crystal X-ray diffraction study and symmetry analysis of the transition mechanism Physics and Chemistry of Minerals 19 528-54419930293
0007744CryoliteYang H, Ghose S, Hatch D M (1993) Ferroelastic phase transition in cryolite, Na3AlF6, a mixed fluoride perovskite: high temperature single crystal X-ray diffraction study and symmetry analysis of the transition mechanism Physics and Chemistry of Minerals 19 528-54419930293
0007745CryoliteYang H, Ghose S, Hatch D M (1993) Ferroelastic phase transition in cryolite, Na3AlF6, a mixed fluoride perovskite: high temperature single crystal X-ray diffraction study and symmetry analysis of the transition mechanism Physics and Chemistry of Minerals 19 528-54419930293
0007746CryoliteYang H, Ghose S, Hatch D M (1993) Ferroelastic phase transition in cryolite, Na3AlF6, a mixed fluoride perovskite: high temperature single crystal X-ray diffraction study and symmetry analysis of the transition mechanism Physics and Chemistry of Minerals 19 528-54419930293
0007747CryoliteYang H, Ghose S, Hatch D M (1993) Ferroelastic phase transition in cryolite, Na3AlF6, a mixed fluoride perovskite: high temperature single crystal X-ray diffraction study and symmetry analysis of the transition mechanism Physics and Chemistry of Minerals 19 528-54419930293
0007748CryoliteYang H, Ghose S, Hatch D M (1993) Ferroelastic phase transition in cryolite, Na3AlF6, a mixed fluoride perovskite: high temperature single crystal X-ray diffraction study and symmetry analysis of the transition mechanism Physics and Chemistry of Minerals 19 528-54419930293
0007749CryoliteYang H, Ghose S, Hatch D M (1993) Ferroelastic phase transition in cryolite, Na3AlF6, a mixed fluoride perovskite: high temperature single crystal X-ray diffraction study and symmetry analysis of the transition mechanism Physics and Chemistry of Minerals 19 528-54419930293
0007750CryoliteYang H, Ghose S, Hatch D M (1993) Ferroelastic phase transition in cryolite, Na3AlF6, a mixed fluoride perovskite: high temperature single crystal X-ray diffraction study and symmetry analysis of the transition mechanism Physics and Chemistry of Minerals 19 528-54419930293
0017654CryoliteNaray-Szabo S, Sasvari K (1938) Die Struktur des Kryoliths Na3 Al F6 _cod_database_code 1010932 Zeitschrift fur Kristallographie 99 27-3119380293
0014033CryoliteRoss K C, Mitchell R H, Chakhmouradian A R (2003) The crystal structure of synthetic simmonsite, Na2LiAlF6 Journal of Solid State Chemistry 172 95-1012003natural0293
0014034CryoliteRoss K C, Mitchell R H, Chakhmouradian A R (2003) The crystal structure of synthetic simmonsite, Na2LiAlF6 Journal of Solid State Chemistry 172 95-1012003synthetic0293
0014038CryoliteZhou Q, Kennedy B J (2004) High-temperature powder synchrotron diffraction studies of synthetic cryolite Na3AlF6 Journal of Solid State Chemistry 177 654-6592004synthetic0293
0014039CryoliteZhou Q, Kennedy B J (2004) High-temperature powder synchrotron diffraction studies of synthetic cryolite Na3AlF6 Journal of Solid State Chemistry 177 654-6592004synthetic0293
0014040CryoliteZhou Q, Kennedy B J (2004) High-temperature powder synchrotron diffraction studies of synthetic cryolite Na3AlF6 Journal of Solid State Chemistry 177 654-6592004synthetic0293
CIF Raw Data - click here to close

Epitaxial Relationships of CryoliteHide

Epitaxial Minerals:
Epitaxy Comments:
Oriented growths (artificial material).

X-Ray Powder DiffractionHide

Image Loading

Radiation - Copper Kα
Data Set:
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
d-spacingIntensity
2.748 Å(100)
1.943 Å(95)
3.886 Å(65)
4.54 Å(55)
4.44 Å(40)
1.571 Å(35)
2.337 Å(30)
Comments:
Synthetic. ICDD 25-772.

Geological EnvironmentHide

Paragenetic Mode(s):
Geological Setting:
Late stage mineral in granitic pegmatites, vapor phase mineral in rhyolites.

Type Occurrence of CryoliteHide

General Appearance of Type Material:
Massive white transparent to translucent.
Place of Conservation of Type Material:
University of Copenhagen, Denmark
Geological Setting of Type Material:
As a pegmatitic body in a granite stock intruded into gneiss.
Associated Minerals at Type Locality:

Synonyms of CryoliteHide

Other Language Names for CryoliteHide

Asturian:Criolita
Catalan:Criolita
Czech:Kryolit
Danish:Kryolit
Dutch:Cryoliet
Estonian:Krüoliit
Italian:Criolite
Japanese:氷晶石
Norwegian:Kryolitt
Norwegian (Nynorsk):Kryolitt
Polish:Kriolit
Portuguese:Criolita
Simplified Chinese:冰晶石
Slovenian:Kriolit
Spanish:Criolita
Sundanese:Kriolit
Ukrainian:Кріоліт
Vietnamese:Cryôlit

Relationship of Cryolite to other SpeciesHide

Other Members of this group:
ElpasoliteK2NaAlF6Iso. m3 (2/m 3) : Pa3
SimmonsiteNa2LiAlF6Mon.

Common AssociatesHide

Associated Minerals Based on Photo Data:
125 photos of Cryolite associated with SideriteFeCO3
73 photos of Cryolite associated with ThomsenoliteNaCa[AlF6] · H2O
25 photos of Cryolite associated with ChalcopyriteCuFeS2
24 photos of Cryolite associated with GalenaPbS
21 photos of Cryolite associated with FluoriteCaF2
20 photos of Cryolite associated with QuartzSiO2
18 photos of Cryolite associated with Hydrokenoralstonite Na0.5(Al,Mg)2(F,OH)6 · H2O
16 photos of Cryolite associated with PachnoliteNaCa[AlF6] · H2O
15 photos of Cryolite associated with CryolithioniteNa3Al2(LiF4)3
14 photos of Cryolite associated with TopazAl2(SiO4)(F,OH)2

Related Minerals - Strunz-mindat GroupingHide

3.CB.05CryolithioniteNa3Al2(LiF4)3Iso. m3m (4/m 3 2/m) : Ia3d
3.CB.15ElpasoliteK2NaAlF6Iso. m3 (2/m 3) : Pa3
3.CB.15SimmonsiteNa2LiAlF6Mon.
3.CB.20ColquiriiteCaLi[AlF6]Trig.
3.CB.25WeberiteNa2Mg[AlF6]FOrth. mmm (2/m 2/m 2/m) : Immm
3.CB.25LeonardseniteMgAlF5 · 2H2O Orth. mmm (2/m 2/m 2/m) : Imma
3.CB.30KarasugiteSrCa[Al(F,OH)7]Mon. 2/m : P21/b
3.CB.35UsoviteBa2CaMgAl2F14Mon. 2/m : B2/b
3.CB.40PachnoliteNaCa[AlF6] · H2OMon. 2/m
3.CB.40ThomsenoliteNaCa[AlF6] · H2OMon. 2/m : P21/b
3.CB.45CarlhintzeiteCa2[AlF6]F · H2OTric.
3.CB.50YaroslaviteCa3Al2F10(OH)2 · H2OOrth.
3.CB.55SbacchiiteCa2AlF7Orth. mmm (2/m 2/m 2/m) : Pnma
3.CB.60VerneiteNa2Ca3Al2F14Iso. 2 3 : I21 3

Other InformationHide

Thermal Behaviour:
Melting Point: 1020°. Inverts to an isometric form at about 560°. Weakly thermoluminescent.
Notes:
Soluble in H2SO4 with evolution of HF. Slightly soluble in water. Readily soluble in AlCl3 solution.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Industrial Uses:
Synthetically produced material is an important electrolyte for the production of aluminium from bauxite (Bayer and Hall–Héroult processes).

Internet Links for CryoliteHide

References for CryoliteHide

Reference List:

Localities for CryoliteHide

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.

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.
Brazil
 
  • Amazonas
    • Presidente Figueiredo
Horbe et al. (1991)
Horbe et al. (1999) +4 other references
  • Santa Catarina
G. Traversa et al. +1 other reference
Canada
 
    • Montérégie
      • La Vallée-du-Richelieu RCM
        • Mont Saint-Hilaire
166-175. +2 other references
      • Lajemmerais RCM
        • Varennes & St-Amable
Horváth et al. (1998)
Horváth et al. (1998)
    • Montréal
176-178. +2 other references
Czech Republic
 
  • Karlovy Vary Region
    • Karlovy Vary District
      • Boží Dar
Bull. Minéral.
  • Ústí nad Labem Region
    • Teplice District
Bull. Minéral.
Europe
 
  • Ore Mountains
Bull. Minéral.
Greenland
 
  • Qeqqata
    • Kangerlussuaq Fjord (Søndre Strømfjord)
Pauly (1946)
  • Sermersooq
    • Arsuk Fjord
Breiter et al. (2024)
Scherer's Allg. Journal D. Chemie (1799) +2 other references
Kazakhstan
 
  • Abai Region
    • Tarbagatai Range
      • Akzhaylyautas Mts (Akzhailyautas Mts; Akjaylautas Mts; Akzhalautas Mts)
Pavel.M. Kartashov (n.d.) +1 other reference
Mali
 
  • Kidal Region
    • Tessalit Cercle
Liégeois et al. (1984) +3 other references
Namibia
 
  • Khomas Region
    • Windhoek Rural
      • Aris
Uwe Kolitsch (single-crystal X-ray diffraction) +3 other references
  • Otjozondjupa Region
    • Otjiwarongo Constituency
      • Kalkfeld
American Mineralogist +1 other reference
Buhn et al. (2002)
Nigeria
 
  • Nasarawa
44-61 Earth Sciences Research Journal +4 other references
  • Plateau
Bailey
Am Min 51:299-323
Bailey
Bailey
Bailey
Norway
 
  • Viken
    • Lunner
Eldjarn (1981) +1 other reference
Poland
 
  • Silesian Voivodeship
    • Wodzisław County
      • Radlin
Łukasz Kruszewski (2012)
Romania
 
  • Harghita County
Hirtopanu (2006)
Russia
 
  • Buryatia
    • Mama River Basin
      • Maigunda River
Bailey +2 other references
  • Chelyabinsk Oblast
    • Ilmen Mountains
Bailey +1 other reference
  • Murmansk Oblast
...
Volume 2: Minerals [Минералы]. Nauka et al. (in Russian) +6 other references
... +1 other reference
    • Lovozersky District
Pekov (1998) +1 other reference
      • Karnasurt Mountain
        • Karnasurt mine
Pekov et al. (2008)
  • Primorsky Krai
    • Khorolsky District
Bailey
  • Tuva
    • Kaa-Khemsky District
Bailey
Pavel.M. Kartashov (n.d.) +1 other reference
  • Zabaykalsky Krai
    • Kalarsky District
USGS Open File Report 2005-1252 p20 +5 other references
Saint Helena, Ascension and Tristan da Cunha
 
Bailey
Spain
 
  • Aragon
    • Huesca
      • Sallent de Gállego
Am Min 51:299-323
  • Canary Islands
    • Santa Cruz de Tenerife Province
      • Tenerife
Dill et al. (2023)
Dill et al. (2023)
Ukraine
 
  • Donetsk Oblast
    • Azov Sea Region
Sharygin (2015)
  • Zhytomyr Oblast
    • Korosten Raion
Bailey +2 other references
    • Zhytomyr Raion
Bailey +2 other references
USA
 
  • California
    • San Diego County
      • Ramona Mining District
        • Ramona
David London et al. (2016)
  • Colorado
    • Boulder County
      • Jamestown Mining District
Eckel et al. (1997)
    • El Paso County
- (2005)
- (2005)
Palache et al. (1951) +1 other reference
Gross et al. (1966)
Gross et al. (1966)
Landes (1935) +1 other reference
- (2005)
    • Fremont County
Armbrustmacher (1988) +1 other reference
Eckel et al. (1997)
Eckel et al. (1997)
Eckel et al. (1997)
    • Garfield County
Eckel et al. (1997)
    • Jefferson County
      • Clear Creek pegmatite Province
Meeves et al. (1966)
    • Rio Blanco County
Eckel et al. (1997)
Tank (1972) +2 other references
  • Nevada
    • Mineral County
      • Fitting Mining District
        • Gillis Range
Mineralogical Record: 31: 204.
  • New Hampshire
    • Grafton County
      • Grafton
  • New Mexico
    • Colfax County
      • Springer
        • Point of Rocks Mesa (Pecks Mesa)
DeMark (1989) +1 other reference
  • Texas
    • Hudspeth County
Am. Min. 74:865-869 (1989)
Am Min 72:1122-1130 +2 other references
  • Utah
    • Emery County
Bullock (1981)
  • Virginia
    • Amelia County
      • Winterham
Kearns (1995) +1 other reference
  • Wisconsin
    • Marathon County
      • Wausau Intrusive Complex
        • Nine Mile pluton
Rocks & Min. (2007)
Bailey
 
Mineral and/or Locality  
Mindat Discussions Facebook Logo Instagram Logo Discord Logo
Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2024, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: March 29, 2024 02:31:39
Go to top of page