Dawsonite
A valid IMA mineral species - grandfathered
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About Dawsonite
John William Dawson
Formula:
NaAlCO3(OH)2
Colour:
Colourless to white; rarely pink; colourless in transmitted light
Lustre:
Vitreous, Silky
Hardness:
3
Specific Gravity:
2.436
Crystal System:
Orthorhombic
Name:
Named by B.J. Harrington in 1874 in honor of Sir John William Dawson (13 October 1820, Pictou, Nova Scotia, Canada - 19 November 1899, Montreal, Quebec, Canada), Principal of McGill University and geologist, who first collected the mineral.
Unique Identifiers
Mindat ID:
1240
Long-form identifier:
mindat:1:1:1240:5
Similar Names
| Dadsonite | A valid IMA mineral species | Pb23Sb25S60Cl |
| Damsonite | A variety of 'Chalcedony' [Quartz] | SiO2 |
| Dyssnite | A variety of Rhodonite | CaMn3Mn(Si5O15) |
| Lawsonite | A valid IMA mineral species - grandfathered | CaAl2(Si2O7)(OH)2 · H2O |
| Mawsonite | A valid IMA mineral species | Cu6Fe2SnS8 |
| Tausonite | A valid IMA mineral species | SrTiO3 |
| Tysonite | A synonym of 'Fluocerite' |
IMA Classification of Dawsonite
Approved, 'Grandfathered' (first described prior to 1959)
First published:
1874
Classification of Dawsonite
5.BB.10
5 : CARBONATES (NITRATES)
B : Carbonates with additional anions, without H2O
B : With alkalies, etc.
5 : CARBONATES (NITRATES)
B : Carbonates with additional anions, without H2O
B : With alkalies, etc.
16a.3.8.1
16a : ANHYDROUS CARBONATES CONTAINING HYDROXYL OR HALOGEN
3 : (AB)2(XO3)Zq
16a : ANHYDROUS CARBONATES CONTAINING HYDROXYL OR HALOGEN
3 : (AB)2(XO3)Zq
11.7.3
11 : Carbonates
7 : Carbonates of Al
11 : Carbonates
7 : Carbonates 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 |
|---|---|---|
| Dws | 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 Dawsonite
Vitreous, Silky
Transparency:
Transparent
Colour:
Colourless to white; rarely pink; colourless in transmitted light
Streak:
White
Hardness:
3 on Mohs scale
Cleavage:
Perfect
On {110}
On {110}
Density:
2.436 g/cm3 (Measured) 2.431 g/cm3 (Calculated)
Optical Data of Dawsonite
Type:
Biaxial (-)
RI values:
nα = 1.466 nβ = 1.542 nγ = 1.596
2V:
Measured: 77° , Calculated: 76°
Max. Birefringence:
δ = 0.130
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:
None to Very Low
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.
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.
Dispersion:
relatively weak r < v
Chemistry of Dawsonite
Mindat Formula:
NaAlCO3(OH)2
Element Weights:
Crystallography of Dawsonite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Imma
Cell Parameters:
a = 6.759 Å, b = 10.425 Å, c = 5.585 Å
Ratio:
a:b:c = 0.648 : 1 : 0.536
Unit Cell V:
393.53 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Bladed to acicular crystals forming incrustations and rosettes; tufts of fine needles. Crystals elongated [001], to 3.5cm.
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) |
|---|---|---|---|---|---|---|---|
| 0015709 | Dawsonite | Chinh L T, Pobedimskaya E A, Khomyakov A P (1987) Crystal structure of dawsonite, NaAl(CO3)(OH)2 and its first discovery in the Khibiny alkaline massiv Vestnik Moskovskogo Universiteta Geologiya 42 74-77 | 1987 | Khibiny alkaline massif, Kola peninsula, Russia | 0 | 293 | |
| 0018528 | Dawsonite | Corazza E, Sabelli C, Vannucci S (1977) Dawsonite: new mineralogical data and structure refinement Neues Jahrbuch fur Mineralogie, Monatshefte 1977 381-397 | 1977 | Terlano, Bolzano, Italy | 0 | 293 | |
| 0005083 | Dawsonite | Frueh A J, Golightly J P (1967) The crystal structure of dawsonite NaAl(CO3)(OH)2 The Canadian Mineralogist 9 51-56 |  | 1967 | McGill University, Montreal, Quebec, Canada | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Loading XRD data...
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.67 Å | (100) |
| 2.784 Å | (90) |
| 2.601 Å | (70) |
| 1.988 Å | (70) |
| 1.728 Å | (70) |
| 3.38 Å | (60) |
| 2.151 Å | (60) |
Comments:
Mont Saint-Bruno, Quebec, Canada. Data from Mandarino and Harris (1965).
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 22 : Hydration and low-𝑇 subsurface aqueous alteration (see also #23) | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 48 : Soil leaching zone minerals | <0.6 |
| 50 : Coal and/or oil shale minerals | <0.36 |
Geological Setting:
Nepheline syenites, authigenic in alkaline shales and coal bearing rocks, saline soils on nepheline tuffs.
Type Occurrence of Dawsonite
General Appearance of Type Material:
Thin bladed crystals.
Place of Conservation of Type Material:
McGill University, Montreal, Quebec, Canada, RMF2381A.
Geological Setting of Type Material:
Feldspathic dike cutting Trenton limestone.
Associated Minerals at Type Locality:
Other Language Names for Dawsonite
Varieties of Dawsonite
| Chromium-bearing Dawsonite | A chromium-bearing variety of dawsonite. |
Common Associates
Associations Based on Photo Data:
| 33 photos of Dawsonite associated with Fluorite | CaF2 |
| 30 photos of Dawsonite associated with Quartz | SiO2 |
| 25 photos of Dawsonite associated with Calcite | CaCO3 |
| 19 photos of Dawsonite associated with Weloganite | Na2Sr3Zr(CO3)6 · 3H2O |
| 14 photos of Dawsonite associated with Sodalite | Na4(Si3Al3)O12Cl |
| 13 photos of Dawsonite associated with Analcime | Na(AlSi2O6) · H2O |
| 12 photos of Dawsonite associated with Siderite | FeCO3 |
| 11 photos of Dawsonite associated with Aegirine | NaFe3+Si2O6 |
| 11 photos of Dawsonite associated with Gmelinite-Na | Na4(Si8Al4)O24 · 11H2O |
| 9 photos of Dawsonite associated with Catapleiite | Na2Zr(Si3O9) · 2H2O |
Related Minerals - Strunz-mindat Grouping
| 5.BB.05 | Barentsite | Na7Al(HCO3)2(CO3)2F4 |
| 5.BB.15 | Tunisite | NaCa2Al4(CO3)4(OH)8Cl |
| 5.BB.20 | Sabinaite | Na4Zr2TiO4(CO3)4 |
Other Information
Notes:
Soluble in acids with effervescence.
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 Dawsonite
mindat.org URL:
https://www.mindat.org/min-1240.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Dawsonite
Reference List:
Frueh, A. J., Golightly, J. P. (1967) The crystal structure of dawsonite NaAl(CO3)(OH)2. The Canadian Mineralogist, 9 (1) 51-56
KWON, Sang Wook, KIM, Byong Ho, ISHIKAWA, Heishichi (1971) The Conditions of Formation of Dawsonite and Its Crystal Structure. The Journal of the Society of Chemical Industry, Japan, 74. 2411-2415 doi:10.1246/nikkashi1898.74.12_2411
Serna, Carlos J., García-Ramos, José V., Peña, Maria J. (1985) Vibrational study of dawsonite type compounds MAl(OH)2CO3 (M = Na, K, NH4). Spectrochimica Acta Part A: Molecular Spectroscopy, 41 (5). 697-702 doi:10.1016/0584-8539(85)80177-x
Ferrini, V.; Martarelli, L.; De Vito, C.; Cina, A.; Deda, T. (2003) The Koman dawsonite and realgar-orpiment deposit, northern Albania: inferences on processes of formation. The Canadian Mineralogist, 41 (2). 413-427 doi:10.2113/gscanmin.41.2.413
Frost, Ray L., Bouzaid, Jocelyn M. (2007) Raman spectroscopy of dawsonite NaAl(CO3)(OH)2. Journal of Raman Spectroscopy, 38 (7) 873-879 doi:10.1002/jrs.1733
Łodziana, Zbigniew, Stoica, Georgiana, Pérez-Ramírez, Javier (2011) Reevaluation of the Structure and Fundamental Physical Properties of Dawsonites by DFT Studies. Inorganic Chemistry, 50 (6) 2590-2598 doi:10.1021/ic102443h
Comerio, Marcos; Morosi, Martín E.; Tunik, Maisa; Paredes, José M.; Zalba, Patricia E. (2014) The role of telogenetic injection of magmatically derived CO2 in the formation of dawsonite from the Castillo Formation, Chubut Group, Patagonia, Argentina. The Canadian Mineralogist, 52 (3). 513-531 doi:10.3749/canmin.52.3.513
Localities for Dawsonite
Showing 140 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.
Albania | |
| ALLIU (2024) |
| Palache et al. (1951) +1 other reference |
Algeria | |
| Palache et al. (1951) |
Angola | |
| Borst et al. (2023) |
Argentina | |
| Zalba et al. (2011) |
Australia | |
| Goldbery et al. (1970) +1 other reference | |
| Keith F Compton collection |
Austria | |
| C.Auer (2015) |
| Exel (1993) |
| Exel (1993) |
Belgium | |
| Hatert et al. (2002) |
| Van Tassel (1962) +3 other references | |
Bolivia | |
| Petrov (n.d.) +1 other reference |
Canada | |
| Peatfield (n.d.) |
| Higgins (1985) +1 other reference |
| Grice (1989) |
| Sabina (1986) |
| STEVENSON et al. (1977) +2 other references |
| Horváth et al. (1998) |
| Horváth et al. (1998) | |
| Can Mineral August 1978 v. 16 no. 3 p. ... +1 other reference |
| JAMBOR et al. (1976) +3 other references |
| Sabina (1983) | |
| Dolan (1923) |
| Dawsonite | |
| HARRINGTON (1874 & 1978) +2 other references | |
| Harrington (1883) | |
| Canadian Museum of Nature collection |
| Tarassoff (2013) | |
| STEVENSON et al. (1977) | |
| Egan (1986) |
China | |
| Yuqiao Gao and Li Liu (2007) |
| Qin et al. (2021) +2 other references |
| Yang et al. (2026) | |
| Yang et al. (2026) | |
| Yuqiao Gao et al. (2008) |
| Fei et al. (2022) |
Czech Republic | |
| Žáček et al. (1992) +1 other reference |
| Kristek et al. (2026) |
Denmark | |
| Thomas et al. (2011) |
Ethiopia | |
| López-García et al. (2020) |
Germany | |
| Schäfer et al. (2018) |
Hungary | |
| Baksa +2 other references |
| Szakáll et al. (1996) | |
Italy | |
| Di Domenico D. (2011) | |
| Di Domenico et al. (2011) |
| Di Domenico et al. (2011) | |
| luigi mattei | |
| 153-160 +1 other reference |
| https://www.mineralatlas.eu/?l=62330 | |
| Exel (1987) |
| Giovanni Scapin Collection |
| Meli (2000) |
| AGMT (Associazione Geomineralogica Toscana) | |
| AGMT (Associazione Geomineralogica Toscana) | |
| Del Caldo et al. (1973) |
| Del Caldo et al. (1973) | |
| [var: Chromium-bearing Dawsonite] Ciampalini et al. (2010) +1 other reference |
| [var: Chromium-bearing Dawsonite] Malesani et al. (1971) +1 other reference | |
| Orlandi et al. (1994) +1 other reference |
| Orlandi et al. (2009) |
| Orlandi et al. (1994) +1 other reference |
| Orlandi et al. (1994) |
| Guelfi et al. (1987) | |
| Orlandi et al. (2009) | |
| Orlandi et al. (2009) |
| Orlandi et al. (2009) | |
| Biagioni C. et al. (2019) | |
| Orlandi (2005) |
| [var: Chromium-bearing Dawsonite] |
| Palache et al. (1951) | |
| https://www.mindat.org/photo-208164.html | |
| Dini (2017) | |
| Boscardin et al. (2011) |
Japan | |
| [var: Chromium-bearing Dawsonite] Hori et al. (1986) |
| Petrov (n.d.) |
| Petrov (n.d.) | |
| Petrov (n.d.) |
Mauritania | |
| Matton et al. (2014) |
| Un Processus Alcalin Péri-Atlantiqu. ... +1 other reference |
Mexico | |
| Megaw (1990) |
Myanmar | |
| Giuliani et al. (2015) |
| Giuliani et al. (2018) |
Namibia | |
| Blancher (2008) |
New Zealand | |
| Railton et al. (1990) | |
Peru | |
| Coveney et al. (1971) |
Poland | |
| Volume 26 +2 other references |
| from a dealer (said to be analyzed) |
Russia | |
| Nishanbaev et al. (2016) |
| Zvezdinskaya L.V. (1995) |
| Volume 2: Minerals [Минералы]. Nauka et al. (in Russian) +9 other references |
| Pavel M. Kartashov (n.d.) | |
| Ruslan Liferovich Collection |
| Pekov et al. (2004) | |
| Pekov (2003) |
| Sokol et al. (2021) |
| Sokol et al. (2021) |
Slovakia | |
| Pauliš |
| Ďuďa R. et al. (1986) |
| Bačo | |
| Ďuďa R. et al. (1986) | |
| Koděra et al. (1986) |
| Myšľan P. (2024) |
| Duda et. all. |
| Ďuďa R. (2001) | |
| Pauliš |
| Ďuďa |
| Ďuďa R. et al. (1986) | |
| Ďuďa |
| Koděra et al. (1986) |
| Martin Števko-unpublished |
South America Plate | |
| Schrank et al. (2024) |
Switzerland | |
| Stalder et al. (1998) +1 other reference |
Tanzania | |
| Hay (1964) +1 other reference |
Ukraine | |
| Belous et al. (1984) |
USA | |
| Bailey (1902) +1 other reference |
| Ferguson (1932) +5 other references |
| [var: Chromium-bearing Dawsonite] Dunning (2000) |
| Eckel et al. (1997) |
| Eckel et al. (1997) |
| Eckel et al. (1997) |
| Eckel et al. (1997) |
| Eckel et al. (1997) |
| Eckel et al. (1997) |
| Eckel et al. (1997) |
| Eckel et al. (1997) |
| Eckel et al. (1997) | |
| - (2005) |
| Tank (1972) +4 other references | |
| Abdolmaleki et al. (2026) |
| Sirbescu et al. (2003) |
| Bullock (1981) |
Vietnam | |
| Dumańska-Słowik et al. (2023) |
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