Andersonite
A valid IMA mineral species - grandfathered
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About Andersonite
Charles A. Anderson
Formula:
Na2Ca(UO2)(CO3)3 · 5.33H2O
Formula revised by Mereiter et al. (2026).
Colour:
Bright green to yellow-green.
Lustre:
Vitreous
Hardness:
2½
Specific Gravity:
2.8
Crystal System:
Trigonal
Name:
For Charles A. Anderson (6 June 1902, Bloomington, California, USA - 9 January 1990, Pomona, California, USA), geologist with the United States Geological Survey. He first collected the minerals from the zone that produced andersonite and other uranium minerals.
This page provides mineralogical data about Andersonite.
Unique Identifiers
Mindat ID:
219
Long-form identifier:
mindat:1:1:219:2
Similar Names
| Andersonite (of Riba) | A synonym of 'Amphibole tonalite' |
IMA Classification of Andersonite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Na2Ca(U6+O2)(CO3)3·5-6H2O
First published:
1951
Classification of Andersonite
5.ED.30
5 : CARBONATES (NITRATES)
E : Uranyl Carbonates
D : UO2:CO3 = 1:3
5 : CARBONATES (NITRATES)
E : Uranyl Carbonates
D : UO2:CO3 = 1:3
15.2.5.1
15 : HYDRATED NORMAL CARBONATES
2 : AmBn(XO3)p·xH2O, with (m+n):p > 1:1
15 : HYDRATED NORMAL CARBONATES
2 : AmBn(XO3)p·xH2O, with (m+n):p > 1:1
11.11.12
11 : Carbonates
11 : Carbonates of Cr and U
11 : Carbonates
11 : Carbonates of Cr and U
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 |
|---|---|---|
| Anr | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Pronunciation of Andersonite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Andersonite
Vitreous
Transparency:
Transparent, Translucent
Colour:
Bright green to yellow-green.
Hardness:
2½ on Mohs scale
Density:
2.8 g/cm3 (Measured) 2.86 g/cm3 (Calculated)
Optical Data of Andersonite
Type:
Uniaxial (+)
RI values:
nω = 1.52 nε = 1.54
Max. Birefringence:
δ = 0.020
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:
Low (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 uniaxial interference figure - the conoscopic
(convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis
centred and vertical. The coloured rings are isochromatics, computed with the
same physics as the Michel-Lévy bar above; the dark cross is the isogyre.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Pleochroism:
Visible
Comments:
O = colourless
E = Light yellow
E = Light yellow
Chemistry of Andersonite
Mindat Formula:
Na2Ca(UO2)(CO3)3 · 5.33H2O
Formula revised by Mereiter et al. (2026).
Formula revised by Mereiter et al. (2026).
Element Weights:
Crystallography of Andersonite
Crystal System:
Trigonal
Class (H-M):
3 - Rhombohedral
Space Group:
R3
Cell Parameters:
a = 18 Å, c = 23.83 Å
Ratio:
a:c = 1 : 1.324
Unit Cell V:
6,686.51 ų (Calculated from Unit Cell)
Morphology:
As rhombohedra, pseudocubic or flattened and with complex form development, to 1 cm; typically in crystalline crusts, granular.
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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View
CIF File Best | x | y | z | a | b | c
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Rotation
Stop | Start
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Labels
Console Off | On | Grey | Yellow
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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) |
|---|---|---|---|---|---|---|---|
| 0009746 | Andersonite | Coda A, Della Giusta A, Tazzoli V (1981) The structure of synthetic andersonite, Na2Ca[UO2(CO3)3].x(H2O) (x~5.6) Acta Crystallographica B37 1496-1500 |  | 1981 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 13.0 Å | (100) |
| 7.97 Å | (100) |
| 5.68 Å | (100) |
| 5.22 Å | (100) |
| 3.71 Å | (80) |
| 3.00 Å | (70) |
| 2.21 Å | (70) |
| 4.35 Å | (60) |
| 4.19 Å | (60) |
| 2.79 Å | (60) |
| 1.852 Å | (60) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] | |
| 47f : [Uranyl (U⁶⁺) minerals] | |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 55 : Anthropogenic mine minerals |
Geological Setting:
An uncommon secondary mineral, formed in the oxidized zone of uranium-bearing hydrothermal polymetallic deposits; may be post-mine, coating walls of mine tunnels.
Type Occurrence of Andersonite
Place of Conservation of Type Material:
National Museum of Natural History, Washington, D.C., USA, 106112–106115.
Geological Setting of Type Material:
Post-mining efflorescences on mine walls.
Associated Minerals at Type Locality:
Other Language Names for Andersonite
Dutch:Andersoniet
French:Andersonite
German:Andersonit
Norwegian:Andersonitt
Russian:Андерсонит
Simplified Chinese:水碳钠钙铀矿
Spanish:Andersonita
Traditional Chinese:水碳鈉鈣鈾礦
Common Associates
Associations Based on Photo Data:
| 19 photos of Andersonite associated with Schröckingerite | NaCa3(UO2)(CO3)3(SO4)F · 10H2O |
| 16 photos of Andersonite associated with Zippeite | K3(UO2)4(SO4)2O3(OH) · 3H2O |
| 11 photos of Andersonite associated with Uraninite | UO2 |
| 11 photos of Andersonite associated with Natrozippeite | Na5(UO2)8(SO4)4O5(OH)3 · 12H2O |
| 9 photos of Andersonite associated with Chalcopyrite | CuFeS2 |
| 9 photos of Andersonite associated with Bayleyite | Mg2(UO2)(CO3)3 · 18H2O |
| 8 photos of Andersonite associated with Johannite | Cu(UO2)2(SO4)2(OH)2 · 8H2O |
| 6 photos of Andersonite associated with 'Petrified Wood' | |
| 6 photos of Andersonite associated with 'Sandstone' | |
| 5 photos of Andersonite associated with Čejkaite | Na4(UO2)(CO3)3 |
Related Minerals - Strunz-mindat Grouping
| 5.ED. | Szilagyiite | NaCa3(UO2)(CO3)3(SeO3)F(H2O)6 |
| 5.ED. | Pendevilleite-(Y) | Mg2Y3Al(UO2)2(CO3)7(OH)6(H2O)16 |
| 5.ED. | Paramarkeyite | Ca2(UO2)(CO3)3 · 5H2O |
| 5.ED.05 | Bayleyite | Mg2(UO2)(CO3)3 · 18H2O |
| 5.ED.10 | Swartzite | MgCa(UO2)(CO3)3 · 12H2O |
| 5.ED.15 | Albrechtschraufite | Ca4Mg(UO2)2(CO3)6F2 · 17-18H2O |
| 5.ED.20 | Liebigite | Ca2(UO2)(CO3)3 · 11H2O |
| 5.ED.25 | Rabbittite | Ca3Mg3(UO2)2(CO3)6(OH)4 · 18H2O |
| 5.ED.35 | Grimselite | K3Na(UO2)(CO3)3 · H2O |
| 5.ED.40 | Widenmannite | Pb2(OH)2[(UO2)(CO3)2] |
| 5.ED.45 | Znucalite | Zn10Ca0.83(UO2)0.83(CO3)4(OH)15.31(H2O)5.48 |
| 5.ED.50 | Agricolaite | K4(UO2)(CO3)3 |
| 5.ED.50 | Čejkaite | Na4(UO2)(CO3)3 |
| 5.ED.55 | Línekite | K2Ca3[(UO2)(CO3)3]2 · 8H2O |
| 5.ED.55 | Braunerite | K2Ca(UO2)(CO3)3 · 6H2O |
| 5.ED.60 | Leószilárdite | Na6Mg(UO2)2(CO3)6 · 6H2O |
| 5.ED.65 | Pseudomarkeyite | Ca8(UO2)4(CO3)12 · 21H2O |
| 5.ED.65 | Natromarkeyite | Na2Ca8(UO2)4(CO3)13 · 27H2O |
| 5.ED.65 | Markeyite | Ca9(UO2)4(CO3)13 · 28H2O |
| 5.ED.70 | Paddlewheelite | MgCa5Cu2(UO2)4(CO3)12(H2O)33 |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 37.6549% | 9,413,725 | α, β, γ |
| Thorium (Th) | 0.0000% | 0 | α, β, γ |
| Potassium (K) | 0.0000% | 0 | β, γ |
For comparison:
- Banana: ~15 Bq per fruit
- Granite: 1,000–3,000 Bq/kg
- EU exemption limit: 10,000 Bq/kg
Note: Risk is shown relative to daily recommended maximum exposure to non-background radiation of 1000 µSv/year. Note that natural background radiation averages around 2400 µSv/year so in reality these risks are probably extremely overstated! With infrequent handling and safe storage natural radioactive minerals do not usually pose much risk.
Interactive Simulator:
Note: The mass selector refers to the mass of radioactive mineral present, not the full specimen, also be aware that the matrix may also be radioactive, possibly more radioactive than this mineral!
Activity: –
| Distance | Dose rate | Risk |
|---|---|---|
| 1 cm | ||
| 10 cm | ||
| 1 m |
The external dose rate (D) from a radioactive mineral is estimated by summing the gamma radiation contributions from its Uranium, Thorium, and Potassium content, disregarding daughter-product which may have a significant effect in some cases (eg 'pitchblende'). This involves multiplying the activity (A, in Bq) of each element by its specific gamma ray constant (Γ), which accounts for its unique gamma emissions. The total unshielded dose at 1 cm is then scaled by the square of the distance (r, in cm) and multiplied by a shielding factor (μshield). This calculation provides a 'worst-case' or 'maximum risk' estimate because it assumes the sample is a point source and entirely neglects any self-shielding where radiation is absorbed within the mineral itself, meaning actual doses will typically be lower. The resulting dose rate (D) is expressed in microsieverts per hour (μSv/h).
D = ((AU × ΓU) + (ATh × ΓTh) + (AK × ΓK)) / r2 × μshield
Fluorescence of Andersonite
Bright pastel green (a unique color)(SW and LW UV).
Other Information
Notes:
Soluble in water.
Health Risks:
Contains uranium - always wash hands after handling. Avoid inhaling dust when handling or breaking. Never lick or ingest. Avoid prolonged exposure in proximity of the body. Store away from inhabited areas.
Internet Links for Andersonite
mindat.org URL:
https://www.mindat.org/min-219.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
Mineral Dealers:
References for Andersonite
Reference List:
Axelrod, Joseph M., Grimaldi, Frank S., Milton, Charles, Murata, and K. J. (1951) The uranium minerals from the Hillside Mine, Yavapai County, Arizona. American Mineralogist, 36 (1-2) 1-22
Axelrod, Joseph M., Grimaldi, Frank S., Milton, Charles, Murata, and K. J. (1951) The uranium minerals from the Hillside Mine, Yavapai County, Arizona. American Mineralogist, 36 (1-2) 1-22
Urbanec, Zdeněk, Čejka, Jiří (1979) Infrared spectra of liebigite, andersonite, voglite and schroeckingerite. Collection of Czechoslovak Chemical Communications, 44. 10-23 doi:10.1135/cccc19790010
Coda, A., Della Giusta, A., Tazzoli, V. (1981) The structure of synthetic andersonite, Na2Ca[UO2(CO3)3]·xH2O (x≃5.6) Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry, 37 (8) 1496-1500 doi:10.1107/s0567740881006432
Kubatko, K.-A. (2005) Thermodynamics of uranyl minerals: Enthalpies of formation of rutherfordine, UO2CO3, andersonite, Na2CaUO2(CO3)3(H2O)5, and grimselite, K3NaUO2(CO3)3H2O. American Mineralogist, 90 (8) 1284-1290 doi:10.2138/am.2005.1821
Burns, Peter C. (2005) U6+ minerals and inorganic compounds: insights into an expanded structural hierarchy of crystal structures. The Canadian Mineralogist, 43 (6) 1839-1894 doi:10.2113/gscanmin.43.6.1839
Plášil, J., Čejka, J. (2015) A note on the molecular water content in uranyl carbonate mineral andersonite. Journal of GEOsciences, 60 (3) 181-187
Gurzhiy, Vladislav V., Krzhizhanovskaya, Maria G., Izatulina, Alina R., Sigmon, Ginger E., Krivovichev, Sergey V., Burns, Peter C. (2018) Structure Refinement and Thermal Stability Studies of the Uranyl Carbonate Mineral Andersonite, Na2Ca[(UO2)(CO3)3]·(5+x)H2O. Minerals, 8 (12) 586 doi:10.3390/min8120586
Localities for Andersonite
Showing 58 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 | |
| Toubes +1 other reference |
Austria | |
| Tufar (1967) +2 other references |
Czech Republic | |
| Hloušek et al. (2002) |
| Plášil et al. (2015) |
| Olds et al. (2018) | |
| Pauliš P. et al. (Kutna Hora, issue 1) |
| Petr Pauliš +1 other reference |
| SeJkora et al. (2008) | |
France | |
| - (1998) |
Germany | |
| Witzke et al. (1998) |
Greece | |
| Rieck et al. (2018) |
Hungary | |
| Szakáll et al. (1996) |
| Szakáll et al. (1996) |
Italy | |
| Campostrini et al. (2005) |
Japan | |
| The Mineral Species of Japan (5th ed) |
Romania | |
| www.minerals-of-the carpathians.eu (2009) |
Slovakia | |
| Števko M. et al. (2012) |
Spain | |
| CMS analysis +1 other reference |
Sweden | |
| Welin (1958) |
UK | |
| Elton et al. (1992) |
| Alysson Rowan collection |
Ukraine | |
| Liventseva (n.d.) |
USA | |
| Bollin (1958) +2 other references |
| Dana 7:II:236 & 238 +5 other references |
| Kampf et al. (2017) |
| Collection of Alex Earl |
| Carnegie Museum of Natural History ... +1 other reference | |
| Travis Olds collection +1 other reference |
| Haynes (1992) +1 other reference | |
| Jensen et al. (2012) |
| Northrop et al. (1996) |
| Northrop et al. (1996) |
| NMBMMR Memoir 15 Geology and Technology ... | |
| NMBMMR Memoir 15 Geology and Technology ... +1 other reference | |
| NMBMMR Memoir 15 Geology and Technology ... | |
| NMBMMR Memoir 15 Geology and Technology ... | |
| Arthur Montgomery Mineralogy of ... |
| Page et al. (1956) +3 other references |
| Observed underground on the tunnel walls |
| Stanley Evans Collection |
| Rruff specimen number R080133 | |
| Collections of Chris Clemens |
| Bullock (1981) | |
| Thorne (n.d.) +2 other references |
| Bullock (1981) |
| Betts (n.d.) |
| Bullock (1981) | |
| Joe Marty Collection |
| Can Min 14:429-436 |
| Bullock (1981) | |
| Specimen in the British Museum | |
| Uranium Guidebook for the Paradox +1 other reference | |
| Deliens et al. (1991) +2 other references |
| Joe Marty (2015) |
| Travis Olds collection +1 other reference | |
| Rick Dalrymple Collection | |
| Eric Quinter collection |
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Thompsons Mining District, Grand County, Utah, USA