Pachnolite
A valid IMA mineral species - grandfathered
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About Pachnolite
Formula:
NaCa[AlF6] · H2O
Colour:
Colourless, white; colourless in transmitted light
Lustre:
Vitreous
Hardness:
3
Specific Gravity:
2.983
Crystal System:
Monoclinic
Name:
From the Greek πάχνη, frost, and λίθος, stone, in allusion to its appearance.
Dimorph of:
This page provides mineralogical data about Pachnolite.
Unique Identifiers
Mindat ID:
3058
Long-form identifier:
mindat:1:1:3058:4
IMA Classification of Pachnolite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
NaCaAlF6(H2O)
First published:
1863
Classification of Pachnolite
3.CB.40
3 : HALIDES
C : Complex halides
B : Neso-aluminofluorides
3 : HALIDES
C : Complex halides
B : Neso-aluminofluorides
11.6.5.1
11 : HALIDE COMPLEXES
6 : Aluminofluorides - Isolated Octahedra
11 : HALIDE COMPLEXES
6 : Aluminofluorides - Isolated Octahedra
8.6.18
8 : Halides - Fluorides, Chlorides, Bromides and Iodides; also Fluoborates and Fluosilicates
6 : Halides of Al
8 : Halides - Fluorides, Chlorides, Bromides and Iodides; also Fluoborates and Fluosilicates
6 : Halides of Al
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 for Standard |
|---|---|---|
| Phn | 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 Pachnolite
Vitreous
Transparency:
Transparent, Translucent
Colour:
Colourless, white; colourless in transmitted light
Streak:
White
Hardness:
3 on Mohs scale
Tenacity:
Brittle
Cleavage:
Poor/Indistinct
On {001}.
On {001}.
Fracture:
Irregular/Uneven
Density:
2.983 g/cm3 (Measured) 2.97 g/cm3 (Calculated)
Optical Data of Pachnolite
Type:
Biaxial (+)
RI values:
nα = 1.411 nβ = 1.413 nγ = 1.42
Max. Birefringence:
δ = 0.009
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. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
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. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Very High (negative)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
No measured or calculated 2V is on file for this mineral, so the value used here (56°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
No measured or calculated 2V is on file for this mineral, so the value used here (56°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Dispersion:
r > v
Chemistry of Pachnolite
Mindat Formula:
NaCa[AlF6] · H2O
Element Weights:
Crystallography of Pachnolite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Cell Parameters:
a = 12.117(4) Å, b = 10.414(3) Å, c = 15.680(4) Å
β = 90.37(2)°
β = 90.37(2)°
Ratio:
a:b:c = 1.164 : 1 : 1.506
Unit Cell V:
1,978.56 ų (Calculated from Unit Cell)
Z:
16
Morphology:
Crystals prismatic [001], commonly acutely terminated. Terminated by {001} at times. {110} striated parallel to the intersection with {001}. Massive, cleavale to granular; stalactitic masses.
Twinning:
On {100} common, yielding crystals with an orthorhombic appearance; giving a grid pattern in thin section.
Comment:
Non-standard space-group setting F2/d.
Crystallographic forms of Pachnolite
Crystal Atlas:
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Pachnolite no.10 - {100} - Goldschmidt (1913-1926)
Pachnolite no.11 - {100} - Goldschmidt (1913-1926)
3d models and HTML5 code kindly provided by
www.smorf.nl.
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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) |
|---|---|---|---|---|---|---|---|
| 0005195 | Pachnolite | Hawthorne F C, Ferguson R B (1983) The crystal structure of pachnolite The Canadian Mineralogist 21 561-566 |  | 1983 | 0 | 293 |
CIF Raw Data - click here to close
Epitaxial Relationships of Pachnolite
Epitaxial Minerals:
| 'Thomsenolite' | NaCa[AlF6] · H2O |
Epitaxy Comments:
Oriented growths of thomsenolite on pachnolite, with thomsenolite (001) and (110) quasi-parallel to pachnolite (110) and (001). Also with thomsenolite (110) and (110) quasi-parallel to pachnolite (110) and (001).
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.95 Å | (100) |
| 3.26 Å | (10) |
| 3.02 Å | (20) |
| 2.92 Å | (10) |
| 2.79 Å | (70) |
| 2.16 Å | (50) |
| 1.971 Å | (90) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 34 : Complex granite pegmatites | |
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47g : [Halogen-bearing surface weathering minerals] |
Type Occurrence of Pachnolite
Place of Conservation of Type Material:
No designated type material.
Associated Minerals at Type Locality:
Synonyms of Pachnolite
Other Language Names for Pachnolite
Common Associates
Associations Based on Photo Data:
| 53 photos of Pachnolite associated with Thomsenolite | NaCa[AlF6] · H2O |
| 22 photos of Pachnolite associated with Hydrokenoralstonite | Na0.5(Al,Mg)2(F,OH)6 · H2O |
| 17 photos of Pachnolite associated with Cryolite | Na2NaAlF6 |
| 9 photos of Pachnolite associated with Siderite | FeCO3 |
| 5 photos of Pachnolite associated with Paralstonite | BaCa(CO3)2 |
| 3 photos of Pachnolite associated with 'Limonite' | |
| 3 photos of Pachnolite associated with Pyrite | FeS2 |
| 3 photos of Pachnolite associated with Kupletskite | K2NaMn2+7Ti2[Si4O12]2O2(OH)4F |
| 3 photos of Pachnolite associated with Elpidite | Na2ZrSi6O15 · 3H2O |
| 2 photos of Pachnolite associated with Goethite | Fe3+O(OH) |
Related Minerals - Strunz-mindat Grouping
| 3.CB.05 | Cryolithionite | Na3Al2(LiF4)3 |
| 3.CB.15 | Elpasolite | K2NaAlF6 |
| 3.CB.15 | Simmonsite | Na2LiAlF6 |
| 3.CB.15 | Cryolite | Na2NaAlF6 |
| 3.CB.20 | Colquiriite | CaLi[AlF6] |
| 3.CB.25 | Leonardsenite | MgAlF5 · 2H2O |
| 3.CB.25 | Weberite | Na2Mg[AlF6]F |
| 3.CB.30 | Karasugite | SrCa[Al(F,OH)7] |
| 3.CB.35 | Usovite | Ba2CaMgAl2F14 |
| 3.CB.40 | Thomsenolite | NaCa[AlF6] · H2O |
| 3.CB.45 | Carlhintzeite | Ca2[AlF6]F · H2O |
| 3.CB.50 | Yaroslavite | Ca3Al2F10(OH)2 · H2O |
| 3.CB.55 | Sbacchiite | Ca2AlF7 |
| 3.CB.60 | Verneite | Na2Ca3Al2F14 |
Other Information
Notes:
Readily soluble in 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 Pachnolite
mindat.org URL:
https://www.mindat.org/min-3058.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Pachnolite
Reference List:
Des Cloizeaux, Alfred (1882) Notes sur les caractères optiques et cristallographiques de la Pachnolite et de la Thomsénolite. Bulletin de Minéralogie, 5 (9) 310-316 doi:10.3406/bulmi.1882.1767
Cross, W.; Hillebrand, W.F. (1885) Contributions to the mineralogy of the Rocky Mountains. Bulletin 20. US Geological Survey 114 pp. doi:10.3133/b20 p.49
Larsen, E.S.; Berman, H. (1934) The microscopic determination of the nonopaque minerals. Bulletin of the US Geological Survey Vol. 848. US Geological Survey p.1-266. doi:10.3133/b848 p.95
Hawthorne, F. C., Ferguson, R. B. (1983) The crystal structure of pachnolite. The Canadian Mineralogist, 21 (3) 561-566
Localities for Pachnolite
Showing 22 localities.
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.
Argentina | |
| Dina (1993) |
| American Mineralogist (1978) +2 other references | |
Australia | |
| ID by Peter Elliott - South Australia ... |
Brazil | |
| Wegner et al. (1998) |
Finland | |
| Ilkka Mikkola collection |
Germany | |
| Dill et al. (2009) |
| web.archive.org (2001) |
Greenland (TL) | |
| Palache et al. (1951) +3 other references |
Norway | |
| Raade et al. (1980) |
Russia | |
| Bailey (1980) +1 other reference |
| Raade et al. (1980) | |
| Starikova et al. (2015) +2 other references |
Ukraine | |
| Liventseva (n.d.) +2 other references |
USA | |
| Palache et al. (1951) +1 other reference |
| Gross et al. (1966) | |
| Am Min 51:299-323 | |
| Eckel et al. (1997) | |
| Landes (1935) +2 other references | |
| Armbrustmacher (1988) +1 other reference |
| AmMin 67:1258 |
| Mandarino (2000) |
| Kearns (1995) +1 other reference |
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Ivigtut Mine, Ivigtut stock, Arsuk Fjord, Sermersooq, Greenland