Sellaite
A valid IMA mineral species - grandfathered
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About Sellaite
Quintino Sella
Formula:
MgF2
Colour:
Colourless, white; colourless in transmitted light.
Lustre:
Vitreous
Hardness:
5 - 5½
Specific Gravity:
3.15
Crystal System:
Tetragonal
Name:
Named for Quintino Sella (7 July 1827, Sella di Mosso, Piedmont, Italy – 14 March 1884), Italian politician, mining engineer, and mineralogist.
Visit gemdat.org for Unique Identifiers
Mindat ID:
3614
Long-form identifier:
mindat:1:1:3614:2
IMA Classification of Sellaite
Approved, 'Grandfathered' (first described prior to 1959)
First published:
1869
Classification of Sellaite
3.AB.15
3 : HALIDES
A : Simple halides, without H2O
B : M:X = 1:2
3 : HALIDES
A : Simple halides, without H2O
B : M:X = 1:2
9.2.2.1
9 : NORMAL HALIDES
2 : AX2
9 : NORMAL HALIDES
2 : AX2
8.4.1
8 : Halides - Fluorides, Chlorides, Bromides and Iodides; also Fluoborates and Fluosilicates
4 : Halides of the alkaline earths and Mg
8 : Halides - Fluorides, Chlorides, Bromides and Iodides; also Fluoborates and Fluosilicates
4 : Halides of the alkaline earths and Mg
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference |
|---|---|---|
| Sel | 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 Sellaite
Vitreous
Transparency:
Transparent
Colour:
Colourless, white; colourless in transmitted light.
Streak:
White
Hardness:
5 - 5½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
On {010} and {110}.
On {010} and {110}.
Fracture:
Conchoidal
Density:
3.15 g/cm3 (Measured) 3.08 g/cm3 (Calculated)
Optical Data of Sellaite
Type:
Uniaxial (+)
RI values:
nω = 1.378 nε = 1.39
Max. Birefringence:
δ = 0.012
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars.
Surface Relief:
Moderate
Chemistry of Sellaite
Mindat Formula:
MgF2
Elements listed:
Crystallography of Sellaite
Crystal System:
Tetragonal
Class (H-M):
4/mmm (4/m 2/m 2/m) - Ditetragonal Dipyramidal
Space Group:
P42/mnm
Setting:
P42/mnm
Cell Parameters:
a = 4.6213(2) Å, c = 3.0519(1) Å
Ratio:
a:c = 1 : 0.66
Unit Cell V:
65.18 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Crystals stout prismatic to acicular [001]. Fibrous aggregates.
Twinning:
On {011}.
Crystal Structure
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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) |
|---|---|---|---|---|---|---|---|
| 0009163 | Sellaite | Baur W H (1956) Uber die verfeinerung der kristallstrukturbestimmung einiger vertreter des rutiltyps: TiO2, SnO2, GeO2 und MgF2 Acta Crystallographica 9 515-520 |  | 1956 | 0 | 293 | |
| 0009407 | Sellaite | Baur W H, Khan A A (1971) Rutile-type compounds. VI. SiO2, GeO2 and a comparison with other rutile-type structures Acta Crystallographica B27 2133-2139 | | 1971 | 0 | 293 | |
| 0011754 | Sellaite | Wyckoff R W G (1963) Second edition. Interscience Publishers, New York, New York Rutile structure Crystal Structures 1 239-444 | 1963 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.275 Å | (100) |
| 2.231 Å | (95) |
| 1.711 Å | (75) |
| 2.067 Å | (35) |
| 1.375 Å | (35) |
| 1.635 Å | (30) |
| 2.545 Å | (20) |
Comments:
Synthetic. The data are from Swanson et al. (1955).
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4a: Earth’s earliest continental crust | >4.4-3.0 |
| 19 : Granitic intrusive rocks | |
| Near-surface Processes | |
| 25 : Evaporites (prebiotic) | |
| High-? alteration and/or metamorphism | |
| 31 : Thermally altered carbonate, phosphate, and iron formations | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 36 : Carbonatites, kimberlites, and related igneous rocks | |
| 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) |
Geological Setting:
Evaporites, volcanic ejecta and fumeroles, marble, magnesites, alkalic granite.
Type Occurrence of Sellaite
Place of Conservation of Type Material:
Muséum Nationale d’Histoire Naturelle, Paris, France, number 97.32, 180.52 (type).
Université Torino, Torino, Italy (type).
Université Torino, Torino, Italy (type).
Geological Setting of Type Material:
In bituminous dolomite-anhydrite rock in a glacial moraine.
Associated Minerals at Type Locality:
Synonyms of Sellaite
Other Language Names for Sellaite
Relationship of Sellaite to other Species
Structurally related to group(s):
| Rutile Group | M4+O2 |
Common Associates
Associated Minerals Based on Photo Data:
| 29 photos of Sellaite associated with Fluorite | CaF2 |
| 12 photos of Sellaite associated with Quartz | SiO2 |
| 12 photos of Sellaite associated with Sanidine | K(AlSi3O8) |
| 10 photos of Sellaite associated with Magnesite-Siderite Series | |
| 7 photos of Sellaite associated with Beryl | Be3Al2(Si6O18) |
| 7 photos of Sellaite associated with Pseudobrookite | Fe2TiO5 |
| 5 photos of Sellaite associated with Chalcopyrite | CuFeS2 |
| 4 photos of Sellaite associated with Ferroaluminoceladonite | K(Fe2+Al◻)(Si4O10)(OH)2 |
| 4 photos of Sellaite associated with Topaz | Al2(SiO4)(F,OH)2 |
| 4 photos of Sellaite associated with Mullite | Al4+2xSi2-2xO10-x |
Related Minerals - Strunz-mindat Grouping
| 3.AB. | Manuelarossiite | PbCaAlF7 |
| 3.AB. | Fluorocronite | PbF2 |
| 3.AB.05 | Tolbachite | CuCl2 |
| 3.AB.10 | Coccinite | HgI2 |
| 3.AB.20 | Lawrencite | (Fe2+,Ni)Cl2 |
| 3.AB.20 | Scacchite | MnCl2 |
| 3.AB.20 | Chloromagnesite | MgCl2 |
| 3.AB.25 | Fluorite | CaF2 |
| 3.AB.25 | Frankdicksonite | BaF2 |
| 3.AB.25 | Strontiofluorite | SrF2 |
| 3.AB.30 | Tveitite-(Y) | (Y, Na)6Ca6Ca6(Ca,Na)F42 |
| 3.AB.35 | Gagarinite-(Y) | NaCaYF6 |
| 3.AB.35 | Polezhaevaite-(Ce) | NaSrCeF6 |
| 3.AB.35 | Gagarinite-(Ce) | Na(REExCa1-x)(REEyCa1-y)F6 |
| 3.AB.37 | Calcioaravaipaite | PbCa2AlF9 |
| 3.AB.85 | Cotunnite | PbCl2 |
Other Information
Notes:
Crystals exhibit a pale violet light when warmed and cleaved.
Slightly soluble in water.
Very slightly soluble in water. Decomposed by concentrated H2SO4.
Slightly soluble in water.
Very slightly soluble in water. Decomposed by concentrated H2SO4.
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 Sellaite
mindat.org URL:
https://www.mindat.org/min-3614.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
References for Sellaite
Reference List:
Buckley, H. E., Vernon, W. S. (1925) XCIV. The crystal structure of magnesium fluoride. The London, Edinburgh, And Dublin Philosophical Magazine And Journal Of Science, S. 6 Vol. 49 (293) 945-951 doi:10.1080/14786442508634672
Baur, W. H. (1956) Über die Verfeinerung der Kristallstrukturbestimmung einiger Vertreter des Rutiltyps: TiO2, SnO2, GeO2 und MgF2 [On the refinement of the crystal structure determination of some representatives of the rutile type: TiO2, SnO2, GeO2 and MgF2]. Acta Crystallographica, 9 (6) 515-520 doi:10.1107/s0365110x56001388
Baur, W. H. (1976) Rutile-type compounds. V. Refinement of MnO2 and MgF2. Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry, 32 (7) 2200-2204 doi:10.1107/s0567740876007371
Pfaff, K., Staude, S., Markl, G. (2012) On the origin of sellaite (MgF2)-rich deposits in Mg-poor environments. American Mineralogist, 97 (11) 1987-1997 doi:10.2138/am.2012.4113
Curetti, Nadia, Merli, Marcello, Capella, Silvana, Benna, Piera, Pavese, Alessandro (2019) Low-pressure ferroelastic phase transition in rutile-type AX2 minerals: cassiterite (SnO2), pyrolusite (MnO2) and sellaite (MgF2) Physics and Chemistry of Minerals, 46 (10) 987-1002 doi:10.1007/s00269-019-01057-7
Localities for Sellaite
symbol to view information about a locality.
The Locality List
- 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).
All localities listed without proper references should be considered as questionable.
Angola | |
| Amores-Casals et al. (2019) |
Australia | |
| Edith Trybalski |
| Elliott et al. (2024) +1 other reference |
| Ehrig et al. (2012) |
| Ross |
| Bottrill et al. (2008) |
| www.crocoite.com (2001) |
| Bottrill +2 other references |
| Bottrill et al. (2008) | |
| Young (1990) |
| Young (1990) | |
Brazil | |
| Cassedanne et al. (1983) |
Canada | |
| Grice et al. (2005) |
| Grice et al. (1996) | |
| Burns et al. (1992) |
| Grice et al. (2005) |
China | |
| Chen et al. (2022) |
| Yuzhou Li (1990) |
| Yuzhou Li (1990) |
| Huang et al. (2022) |
| Liu et al. (2022) |
| Weifan Ding (1983) +2 other references |
France (TL) | |
| Bariand et al. (n.d.) +3 other references |
| Le règne Minérale +1 other reference |
| Dubru. M (1986) |
| Belot (1978) +1 other reference |
Germany | |
| Walenta (1992) +1 other reference |
| Rondorf et al. (1988) |
| Blass (2010) |
| Blass et al. (2006) |
| Hentschel (1978) |
| Ko Jansen |
| Wittern (2001) |
| Desor et al. (08/2020) |
| Heidorn (1932) +1 other reference |
Greece | |
| Uwe Kolitsch and Branko Rieck analyses (see also http://lavrion.gr/Minerals/Updates.html) |
Italy | |
| Palache et al. (1951) +1 other reference |
| Russo et al. (2014) |
| Russo et al. (2014) | |
| Flamini (1966) +3 other references |
| - (n.d.) +1 other reference |
| - (n.d.) +1 other reference |
| Palache et al. (1951) +3 other references |
| Pelloux (1919) +6 other references |
Kazakhstan | |
| Pekov et al. (1993) |
| Pavel.M. Kartashov (n.d.) |
| Pavel.M. Kartashov (n.d.) |
Kenya | |
| Waweru (2020) |
Namibia | |
| ... |
Norway | |
| |
| Sæbø (1966) +1 other reference |
Peru | |
| Imai et al. (1985) +2 other references |
Poland | |
| Kruszewski et al. (2020) |
Portugal | |
| Found by and in the collection of ... |
Russia | |
| Ларионов Н.Н. +1 other reference |
| Cesnokov et al. (1998) |
| Pekov (1998) |
| Pekov et al. (2015) |
| Pekov et al. (2015) +1 other reference | |
| Vergasova L P et al. (1996) | |
| Pekov et al. (2015) | |
| Shchipalkina et al. (2020) |
| Pekov et al. (2018) | |
| Bailey (1980) |
| Krymsky et al. (2003, April) | |
| Ryazantseva (2001) | |
| Pekov (1998) | |
| V.A. Gorelov (1997) |
| Ivashchenko et al. (2011, September) |
| Palache et al. (1951) |
Spain | |
| Campeny et al. (2023) |
| Dill et al. (2023) |
| Dill et al. (2023) |
| Dill et al. (2023) |
| Dill et al. (2023) |
| Dill et al. (2023) | |
| Dill et al. (2023) | |
| Dill et al. (2023) | |
| Dill et al. (2023) | |
| Dill et al. (2023) | |
Tanzania | |
| Mitchell (1997) +1 other reference |
USA | |
| Eckel et al. (1997) |
| Simmons et al. (1980) |
Uzbekistan | |
| Badalov et al. (1975) |
Zambia | |
| Zambezi et al. (1997) |
Quick NavTopAbout SellaiteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesRelationshipsCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Mount Bischoff Mine, Waratah-Mt Bischoff, Waratah district, Waratah-Wynyard municipality, Tasmania, Australia