Villiaumite
A valid IMA mineral species - grandfathered
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About Villiaumite
Formula:
NaF
Colour:
Dark carmine-red, dark red, light orange, pink
Lustre:
Vitreous
Hardness:
2 - 2½
Specific Gravity:
2.79
Crystal System:
Isometric
Member of:
Name:
Named after Maxime Villiaume, French explorer and officer in the colonial artillery corps stationed in northern Madagascar, for his help in the acquisition of mineral and rock collections from Madagascar and Guinea. The species was first found in his collection.
The Na analogue of carobbiite.
Water-soluble and toxic!
According to Calas et al. (2021) the red colour comes from metal Na nanoparticles, 2.5–3 nm in diameter. Similar nanoparticles impart blue colour to halite.
Water-soluble and toxic!
According to Calas et al. (2021) the red colour comes from metal Na nanoparticles, 2.5–3 nm in diameter. Similar nanoparticles impart blue colour to halite.
Visit gemdat.org for gemological information about Villiaumite.
Unique Identifiers
Mindat ID:
4181
Long-form identifier:
mindat:1:1:4181:8
GUID
(UUID V4):
(UUID V4):
42d8fefb-8883-4090-90b3-7576fc4dd26d
IMA Classification of Villiaumite
Approved, 'Grandfathered' (first described prior to 1959)
First published:
1908
Classification of Villiaumite
3.AA.20
3 : HALIDES
A : Simple halides, without H2O
A : M:X = 1:1, 2:3, 3:5, etc.
3 : HALIDES
A : Simple halides, without H2O
A : M:X = 1:1, 2:3, 3:5, etc.
9.1.1.3
9 : NORMAL HALIDES
1 : AX
9 : NORMAL HALIDES
1 : AX
8.1.2
8 : Halides - Fluorides, Chlorides, Bromides and Iodides; also Fluoborates and Fluosilicates
1 : Halides of the alkali metals and ammonium
8 : Halides - Fluorides, Chlorides, Bromides and Iodides; also Fluoborates and Fluosilicates
1 : Halides of the alkali metals and ammonium
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 |
---|---|---|
Vll | 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 Villiaumite
Vitreous
Transparency:
Transparent
Colour:
Dark carmine-red, dark red, light orange, pink
Comment:
The reddish colours were thought to be due to structural defects, caused by irradiation (Sørensen, 1973; Jahn et al., 2014). However, according to Calas et al. (2021) the red colour comes from metal Na nanoparticles, 2.5–3 nm in diameter.
Villiaumite samples began to change color very slowly after being heated above 300 °C in a muffle furnace. Subsequent color changes required heating at increasingly higher temperatures for approximately 48–72 h. Samples of the reddish mineral villiaumite turned orange, pink and finally colorless (at approximately at 430 °C).[[1]]
Heating is accompanied by strong thermoluminescence (Sørensen, 1973).
Villiaumite samples began to change color very slowly after being heated above 300 °C in a muffle furnace. Subsequent color changes required heating at increasingly higher temperatures for approximately 48–72 h. Samples of the reddish mineral villiaumite turned orange, pink and finally colorless (at approximately at 430 °C).[[1]]
Heating is accompanied by strong thermoluminescence (Sørensen, 1973).
Streak:
White
Hardness:
2 - 2½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
On {001}.
On {001}.
Parting:
Translation gliding with T{011}, t[011], and probably also T{001}, t[011].
Density:
2.79 g/cm3 (Measured) 2.81 g/cm3 (Calculated)
Optical Data of Villiaumite
Type:
Isotropic
RI values:
n = 1.327 - 1.328
Birefringence:
Isotropic minerals have no birefringence
Surface Relief:
Moderate
Pleochroism:
Strong
Comments:
E = yellow
O = pink to deep carmine
O = pink to deep carmine
Comments:
Weak anomalous birefringence.
Chemistry of Villiaumite
Mindat Formula:
NaF
Elements listed:
CAS Registry number:
Crystallography of Villiaumite
Crystal System:
Isometric
Class (H-M):
m3m (4/m 3 2/m) - Hexoctahedral
Space Group:
Fd3m
Cell Parameters:
a = 4.6342 Å
Unit Cell V:
99.52 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Cubic, often rounded crystals; massive, granular.
Crystal Structure
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2x2x2 | 3x3x3 | 4x4x4
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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) |
---|---|---|---|---|---|---|---|
0009251 | Villiaumite | Deshpande V T (1961) Thermal expansion of sodium fluoride and sodium bromide Acta Crystallographica 14 794-794 | 1961 | 0 | 302.6 | ||
0009252 | Villiaumite | Deshpande V T (1961) Thermal expansion of sodium fluoride and sodium bromide Acta Crystallographica 14 794-794 | 1961 | 0 | 341.1 | ||
0009253 | Villiaumite | Deshpande V T (1961) Thermal expansion of sodium fluoride and sodium bromide Acta Crystallographica 14 794-794 | 1961 | 0 | 381 | ||
0009254 | Villiaumite | Deshpande V T (1961) Thermal expansion of sodium fluoride and sodium bromide Acta Crystallographica 14 794-794 | 1961 | 0 | 421 | ||
0009255 | Villiaumite | Deshpande V T (1961) Thermal expansion of sodium fluoride and sodium bromide Acta Crystallographica 14 794-794 | 1961 | 0 | 449 | ||
0009256 | Villiaumite | Deshpande V T (1961) Thermal expansion of sodium fluoride and sodium bromide Acta Crystallographica 14 794-794 | 1961 | 0 | 481 | ||
0009257 | Villiaumite | Deshpande V T (1961) Thermal expansion of sodium fluoride and sodium bromide Acta Crystallographica 14 794-794 | 1961 | 0 | 527 | ||
0011357 | Villiaumite | Wyckoff R W G (1963) Second edition. Interscience Publishers, New York, New York rocksalt structure Crystal Structures 1 85-237 | 1963 | 0 | 293 | ||
0018133 | Villiaumite | Bragg W (1920) Crystal structure of Na F _cod_database_code 1011282 Nature 105 646-648 | 1920 | 0 | 293 | ||
0018029 | Villiaumite | Barth T, Lunde G (1927) Ueber das Mineral Villiaumit _cod_database_code 1011141 Zentralblatt fur Mineralogie und Geologie, A1927 57-66 | 1927 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
d-spacing | Intensity |
---|---|
2.319 Å | (100) |
1.639 Å | (60) |
1.338 Å | (17) |
1.0363 Å | (12) |
0.9458 Å | (8) |
1.1588 Å | (7) |
2.680 Å | (3) |
Comments:
Synthetic.
Geological Environment
Paragenetic Mode(s):
Paragenetic Mode | Earliest Age (Ga) |
---|---|
Near-surface Processes | |
25 : Evaporites (prebiotic) | |
Stage 4b: Highly evolved igneous rocks | >3.0 |
35 : Ultra-alkali and agpaitic igneous rocks |
Geological Setting:
Alkalic rocks.
Type Occurrence of Villiaumite
General Appearance of Type Material:
Carmine red to dark violet masses 1-3 mm in size.
Place of Conservation of Type Material:
Muséum Nationale d’Histoire Naturelle, Paris, France, number 108.220/6 (cotype).
Ecole Nationale Supérieure des Mines, Paris, France, number 51037 (cotype).
Ecole Nationale Supérieure des Mines, Paris, France, number 51037 (cotype).
Geological Setting of Type Material:
Small miarolytic cavities in nepheline syenite.
Other Language Names for Villiaumite
Relationship of Villiaumite to other Species
Member of:
Other Members of this group:
Carobbiite | KF | Iso. m3m (4/m 3 2/m) : Fm3m |
Griceite | LiF | Iso. m3m (4/m 3 2/m) : Fm3m |
Halite | NaCl | Iso. m3m (4/m 3 2/m) : Fm3m |
Sylvite | KCl | Iso. m3m (4/m 3 2/m) : Fm3m |
Common Associates
Associated Minerals Based on Photo Data:
101 photos of Villiaumite associated with Aegirine | NaFe3+Si2O6 |
66 photos of Villiaumite associated with Tuperssuatsiaite | Fe3+Fe3+2(Na◻)◻2Si8O20(OH)2(H2O)4 · 2H2O |
50 photos of Villiaumite associated with Ellingsenite | Na5Ca6Si18O38(OH)13 · 6H2O |
44 photos of Villiaumite associated with Pectolite | NaCa2Si3O8(OH) |
38 photos of Villiaumite associated with Natrolite | Na2Al2Si3O10 · 2H2O |
34 photos of Villiaumite associated with Microcline | K(AlSi3O8) |
22 photos of Villiaumite associated with Fluorite | CaF2 |
18 photos of Villiaumite associated with Thermonatrite | Na2CO3 · H2O |
16 photos of Villiaumite associated with Hilairite | Na2Zr[SiO3]3 · 3H2O |
13 photos of Villiaumite associated with Serandite | NaMn2+2Si3O8(OH) |
Related Minerals - Strunz-mindat Grouping
3.AA. | Brontesite | (NH4)3PbCl5 |
3.AA.05 | Marshite | CuI |
3.AA.05 | Miersite | (Ag,Cu)I |
3.AA.05 | Nantokite | CuCl |
3.AA.05 | UM1999-11:I:CuS | Cu(I,S) |
3.AA.10 | Iodargyrite | AgI |
3.AA.10 | Tocornalite | (Ag,Hg)I |
3.AA.15 | Bromargyrite | AgBr |
3.AA.15 | Chlorargyrite | AgCl |
3.AA.20 | Carobbiite | KF |
3.AA.20 | Griceite | LiF |
3.AA.20 | Halite | NaCl |
3.AA.20 | Sylvite | KCl |
3.AA.25 | Salammoniac | NH4Cl |
3.AA.25 | UM1998-03-Cl:Tl | TlCl |
3.AA.25 | Lafossaite | Tl(Cl,Br) |
3.AA.25 | Nataliyamalikite | TlI |
3.AA.30 | Calomel | [Hg2]2+Cl2 |
3.AA.30 | Kuzminite | [Hg2]2+(Br,Cl)2 |
3.AA.30 | Moschelite | [Hg2]2+I2 |
3.AA.35 | Neighborite | NaMgF3 |
3.AA.35 | Parascandolaite | KMgF3 |
3.AA.40 | Chlorocalcite | KCaCl3 |
3.AA.40 | Javorieite | KFeCl3 |
3.AA.45 | Kolarite | PbTeCl2 |
3.AA.50 | Radhakrishnaite | PbTe3(Cl,S)2 |
3.AA.55 | Challacolloite | KPb2Cl5 |
3.AA.60 | Hephaistosite | TlPb2Cl5 |
3.AA.90 | Pseudocotunnite | K2PbCl4 |
Fluorescence of Villiaumite
Dark red to orange and yellow fluorescence under SW and LW UV.
Other Information
Thermal Behaviour:
Becomes colourless and isotropic when heated to 300° (see also commments on colour). Melts to a thin liquid, becoming white and opaque on cooling.
Notes:
Soluble in water. Strong thermoluminescence.
Health Risks:
Poisonous! Fluoride ion in water-soluble form is what makes this mineral highly toxic. Its availability in macrospecimens, and the attractive colour, might lure small children into tasting it. May be fatal if swallowed or inhaled. Affects respiratory system, heart, skeleton, circulatory system, central nervous system and kidneys. Causes irritation to skin, eyes and respiratory tract. Irritation effects may be delayed.
Wash hands after handling; do not generate dust by grinding or sawing; and keep out of reach of small children.
Oral ld50 close to 50mg/kg (52 in rat, 57 in mouse).
See MSDS Ref. S3722
Wash hands after handling; do not generate dust by grinding or sawing; and keep out of reach of small children.
Oral ld50 close to 50mg/kg (52 in rat, 57 in mouse).
See MSDS Ref. S3722
Internet Links for Villiaumite
mindat.org URL:
https://www.mindat.org/min-4181.html
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References for Villiaumite
Reference List:
forum.amiminerals.it (n.d.) http://forum.amiminerals.it/viewtopic.php?f=5&t=18798&sid=50d6db361ecc540a05883c73ce2015fc
Localities for Villiaumite
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).
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.
All localities listed without proper references should be considered as questionable.
Quick NavTopAbout VilliaumiteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence Other LanguagesRelationshipsCommon AssociatesStrunz-MindatFluorescence Other InformationInternet Links References Localities Locality List
Aris Quarries, Aris, Windhoek Rural, Khomas Region, Namibia