Uranocircite
A valid IMA mineral species - grandfathered
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About Uranocircite
Formula:
Ba(UO2)2(PO4)2 · 10H2O
Colour:
Yellow-green, yellow; pale canary-yellow in transmitted light.
Lustre:
Pearly
Hardness:
2 - 2½
Specific Gravity:
3.46
Crystal System:
Tetragonal
Member of:
Name:
The name reflects its uranium content and its discovery locality, Falkenstein (Falcon's Stone) - the Greek κίρκος for "CIRCes" meaning "falcon." It was renamed to uranocircite-II in 1963, but reverted back to uranocircite in 2022.
Type Locality:
Autunite Group.
Dehydrates rapidly in dry atmospheres at normal temperature to metauranocircite (as metauranocircite-I in Walenta, 1963).
Dehydrates rapidly in dry atmospheres at normal temperature to metauranocircite (as metauranocircite-I in Walenta, 1963).
Unique Identifiers
Mindat ID:
4105
Long-form identifier:
mindat:1:1:4105:4
Similar Names
| Uranocircite I | Ba(UO2)2(PO4)2 · 12H2O |
Classification of Uranocircite
The autunite-type sheet
The autunite-type sheet found in members of the autunite group.
IMA Classification of Uranocircite
Approved, 'Grandfathered' (first described prior to 1959)
IMA status notes:
Renamed by the IMA
IMA Formula:
Ba(U6+O2)2(PO4)2·10H2O
8.EB.05
8 : PHOSPHATES, ARSENATES, VANADATES
E : Uranyl phosphates and arsenates
B : UO2:RO4 = 1:1
8 : PHOSPHATES, ARSENATES, VANADATES
E : Uranyl phosphates and arsenates
B : UO2:RO4 = 1:1
40.2a.3.1
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
2a : AB2(XO4)2·xH2O, containing (UO2)2+
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
2a : AB2(XO4)2·xH2O, containing (UO2)2+
19.11.22
19 : Phosphates
11 : Phosphates of U
19 : Phosphates
11 : Phosphates of 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 |
|---|---|---|
| Urc-II | 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 Uranocircite
Pearly
Transparency:
Transparent, Translucent
Comment:
Lustre pearly on cleavage {001}.
Colour:
Yellow-green, yellow; pale canary-yellow in transmitted light.
Hardness:
2 - 2½ on Mohs scale
Cleavage:
Perfect
Perfect on {001}; distinct on {100} {010}
Perfect on {001}; distinct on {100} {010}
Density:
3.46 g/cm3 (Measured)
Optical Data of Uranocircite
Type:
Biaxial (-)
RI values:
nα = 1.574 nβ = 1.583 nγ = 1.588
2V:
Measured: 70° , Calculated: 72°
Max. Birefringence:
δ = 0.014
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:
Moderate (positive)
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:
none
Pleochroism:
Weak
Comments:
X = Colourless
Y = Z = Pale canary yellow
Y = Z = Pale canary yellow
Comments:
Exhibits sets of twin lamellae parallel to {100} and {010}. The biaxial material, upon heating to 100° - 150°, transitions to uniaxial with the accompanying loss of water to the dihydrate.
Chemistry of Uranocircite
Mindat Formula:
Ba(UO2)2(PO4)2 · 10H2O
Element Weights:
Crystallography of Uranocircite
Crystal System:
Tetragonal
Cell Parameters:
a = 7.01 Å, c = 20.46 Å
Ratio:
a:c = 1 : 2.919
Unit Cell V:
1,005.41 ų (Calculated from Unit Cell)
Morphology:
Thin tabular crystals.
Twinning:
Twin lamellae parallel to {100} and {010}.
Comment:
Interpreted to be isostructural with heinrichite: monoclinic, space group P2/c, a 7.01, b 6.99, c 21.2 .ANG., beta 103.9°, V 1008.4 A3 (Locock et al., 2005)
Epitaxial Relationships of Uranocircite
Epitaxial Minerals:
| 'Autunite' | Ca(UO2)2(PO4)2 · 10-12H2O |
| 'Torbernite' | Cu(UO2)2(PO4)2 · 12H2O |
Epitaxy Comments:
Occurs in parallel growths.
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] |
Geological Setting:
Secondary uranium mineral
Type Occurrence of Uranocircite
Synonyms of Uranocircite
Other Language Names for Uranocircite
Relationship of Uranocircite to other Species
Member of:
Other Members of Autunite Group:
| Autunite | Ca(UO2)2(PO4)2 · 10-12H2O | Orth. mmm(2/m2/m2/m) : Pnma |
| Bassetite | Fe2+(UO2)2(PO4)2 · 10H2O | Mon. 2/m |
| Heinrichite | Ba(UO2)2(AsO4)2 · 10H2O | Mon. 2/m : P2/b |
| Hydronováčekite | Mg(UO2)2(AsO4)2 · 12H2O | Tric. 1 : P1 |
| Kahlerite | Fe2+(UO2)2(AsO4)2 · 12H2O | Tet. 4/m : P42/n |
| Nováčekite | Mg(UO2)2(AsO4)2 · 10H2O | Mon. 2/m |
| Rauchite | Ni(UO2)2(AsO4)2 · 10H2O | Tric. 1 : P1 |
| Sabugalite | HAl(UO2)4(PO4)4 · 16H2O | Mon. 2/m : B2/m |
| Saléeite | Mg(UO2)2(PO4)2 · 10H2O | Mon. 2/m |
| Torbernite | Cu(UO2)2(PO4)2 · 12H2O | Tet. 4/mmm(4/m2/m2/m) : I4/mmm |
| Uranospinite | Ca(UO2)2(AsO4)2 · 10H2O | Tet. 4/mmm(4/m2/m2/m) : P4/nmm |
| Zeunerite | Cu(UO2)2(AsO4)2 · 12H2O | Tet. 4/mmm(4/m2/m2/m) : I4/mmm |
Common Associates
Associations Based on Photo Data:
| 11 photos of Uranocircite associated with Quartz | SiO2 |
| 11 photos of Uranocircite associated with 'Smoky Quartz' | SiO2 |
| 6 photos of Uranocircite associated with Fluorite | CaF2 |
| 5 photos of Uranocircite associated with Orthoclase | K(AlSi3O8) |
| 2 photos of Uranocircite associated with Zircon | Zr(SiO4) |
| 2 photos of Uranocircite associated with Autunite | Ca(UO2)2(PO4)2 · 10-12H2O |
| 2 photos of Uranocircite associated with Torbernite | Cu(UO2)2(PO4)2 · 12H2O |
| 2 photos of Uranocircite associated with Uranophane | Ca(UO2)2(SiO3OH)2 · 5H2O |
| 1 photo of Uranocircite associated with Studtite | [(UO2)(O2)(H2O)2] · H2O |
| 1 photo of Uranocircite associated with Microcline | K(AlSi3O8) |
Related Minerals - Strunz-mindat Grouping
| 8.EB. | Meta-autunite Group | A1-2(UO2)2(TO4)2 · 5-10H2O |
| 8.EB.05 | Rauchite | Ni(UO2)2(AsO4)2 · 10H2O |
| 8.EB.05 | Uranospinite | Ca(UO2)2(AsO4)2 · 10H2O |
| 8.EB.05 | Zeunerite | Cu(UO2)2(AsO4)2 · 12H2O |
| 8.EB.05 | Metarauchite | Ni(UO2)2(AsO4)2 · 8H2O |
| 8.EB.05 | Heinrichite | Ba(UO2)2(AsO4)2 · 10H2O |
| 8.EB.05 | Kahlerite | Fe2+(UO2)2(AsO4)2 · 12H2O |
| 8.EB.05 | Hydronováčekite | Mg(UO2)2(AsO4)2 · 12H2O |
| 8.EB.05 | Torbernite | Cu(UO2)2(PO4)2 · 12H2O |
| 8.EB.05 | Nováčekite | Mg(UO2)2(AsO4)2 · 10H2O |
| 8.EB.05 | Autunite | Ca(UO2)2(PO4)2 · 10-12H2O |
| 8.EB.05 | Saléeite | Mg(UO2)2(PO4)2 · 10H2O |
| 8.EB.05 | Xiangjiangite | (Fe3+,Al)(UO2)4(PO4)2(SO4)2(OH) · 22H2O |
| 8.EB.10 | Bassetite | Fe2+(UO2)2(PO4)2 · 10H2O |
| 8.EB.10 | Lehnerite | Mn2+(UO2)2(PO4)2 · 8H2O |
| 8.EB.10 | Meta-autunite | Ca(UO2)2(PO4)2 · 6H2O |
| 8.EB.10 | Metasaléeite | Mg(UO2)2(PO4)2 · 8H2O |
| 8.EB.10 | Metauranocircite | Ba(UO2)2(PO4)2 · 7H2O |
| 8.EB.10 | Metauranospinite | Ca(UO2)2(AsO4)2 · 8H2O |
| 8.EB.10 | Metaheinrichite | Ba(UO2)2(AsO4)2 · 8H2O |
| 8.EB.10 | Metakahlerite | Fe2+(UO2)2(AsO4)2 · 8H2O |
| 8.EB.10 | Metakirchheimerite | Co(UO2)2(AsO4)2 · 8H2O |
| 8.EB.10 | Metanováčekite | Mg(UO2)2(AsO4)2 · 8H2O |
| 8.EB.10 | Metanatroautunite | Na(UO2)(PO4)(H2O)3 |
| 8.EB.10 | Metatorbernite | Cu(UO2)2(PO4)2 · 8H2O |
| 8.EB.10 | Metazeunerite | Cu(UO2)2(AsO4)2 · 8H2O |
| 8.EB.10 | Przhevalskite | Pb2(UO2)3(PO4)2(OH)4 · 3H2O |
| 8.EB.10 | 'Pseudo-autunite' | (H3O)4Ca2(UO2)2(PO4)4 · 5H2O |
| 8.EB.15 | Abernathyite | K(UO2)(AsO4) · 3H2O |
| 8.EB.15 | Uramphite | (NH4)2(UO2)2(PO4)2 · 6H2O |
| 8.EB.15 | Meta-ankoleite | K2(UO2)2(PO4)2 · 6H2O |
| 8.EB.15 | Natrouranospinite | Na2(UO2)2(AsO4)2 · 5H2O |
| 8.EB.15 | Trögerite | (H3O)(UO2)(AsO4) · 3H2O |
| 8.EB.15 | Chernikovite | (H3O)2(UO2)2(PO4)2 · 6H2O |
| 8.EB.15 | Uramarsite | (NH4)(UO2)(AsO4) · 3H2O |
| 8.EB.20 | Chistyakovaite | Al(UO2)2(AsO4)2(F,OH) · 6.5H2O |
| 8.EB.20 | Threadgoldite | Al(UO2)2(PO4)2(OH) · 8H2O |
| 8.EB.25 | Uranospathite | (Al,◻)(UO2)2(PO4)2F · 20(H2O,F) |
| 8.EB.25 | Arsenuranospathite | Al(UO2)2(AsO4)2F · 20H2O |
| 8.EB.30 | Vochtenite | (Fe2+,Mg)Fe3+(UO2)4(PO4)4(OH) · 12-13H2O |
| 8.EB.35 | Coconinoite | Fe3+2Al2(UO2)2(PO4)4(SO4)(OH)2 · 20H2O |
| 8.EB.40 | Ranunculite | HAl(UO2)(PO4)(OH)3 · 4H2O |
| 8.EB.45 | Triangulite | Al3(UO2)4(PO4)4(OH)5 · 5H2O |
| 8.EB.50 | Furongite | Al13(UO2)7(PO4)13(OH)14 · 58H2O |
| 8.EB.55 | Arsenosabugalite | H0.5Al0.5(UO2)2(AsO4)2 · 8H2O |
| 8.EB.55 | Sabugalite | HAl(UO2)4(PO4)4 · 16H2O |
| 8.EB.60 | Horákite | (Bi7O7OH)[(UO2)4(PO4)2(AsO4)2(OH)2] · 3.5H2O |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 45.4480% | 11,362,000 | 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 Uranocircite
Green
Other Information
Notes:
Radioactive. Soluble in acids.
Health Risks:
Contains uranium. Wash hands after handling. Do not lick or ingest, do not breathe dust when breaking, trimming or otherwise modifying.
Internet Links for Uranocircite
mindat.org URL:
https://www.mindat.org/min-4105.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 Uranocircite
Reference List:
Church, A. H. (1877) VI.—Note on Uranocircite. Mineralogical Magazine and Journal of the Mineralogical Society, 1 (7) 234-236 doi:10.1180/minmag.1877.001.7.06
Gaubert, M. P. (1904) Produits de déshydratation de quelques phosphates et orientation du chlorure de baryum sur les minéraux du groupe de l´autunite. Bulletin de la Société Française de Minéralogie, 27. 222-233
Larsen, Esper S. (1921) The microscopic determination of the nonopaque minerals. Bulletin 679. US Geological Survey doi:10.3133/b679 p.149
Fairchild, J. G. (1929) Base exchange in artificial autunites. American Mineralogist, 14 (7) 265-275
Frondel, Clifford (1958) Systematic mineralogy of uranium and thorium. Bulletin 1064. US Geological Survey doi:10.3133/b1064
Localities for Uranocircite
Showing 107 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.
Australia | |
| Sorrell (n.d.) |
Austria | |
| Neschen (n.d.) |
| Exel (1993) |
Brazil | |
| Bruno Gioia specimen +1 other reference |
| |
Bulgaria | |
| Kalaidjiev et al. (2009) |
| Palache et al. (1951) | |
China | |
| Dahlkamp (2009) |
| National Geological Archives of China ... |
| National Geological Archives of China ... |
| Min et al. (2005) |
| Dahlkamp (2009) |
| Dahlkamp (2009) | |
Czech Republic | |
| Hloušek et al. (2002) |
| M.E. Ciriotti |
| Jirásek et al. (2016) |
| Pauliš P. et al. (Kutna Hora, issue 1) |
| Pauliš P. et al. (Kutna Hora, issue 1) |
| Pauliš P. et al. (Kutna Hora, issue 1) |
| Škácha et al. (2017) |
DR Congo | |
| Gauthier et al. (1989) |
| Dewaele et al. (2016) |
France | |
| Cuchet et al. (2000) |
| R. Pierrot |
| |
| - (1998) |
| - (1998) | |
| OLLIC Pascal Collection +1 other reference |
| J. Geffroy |
| Asselborn (1983) +1 other reference |
| - (1998) |
| Schillinger et al. (2001) |
| - (1998) |
| - (1998) |
| - (1998) |
| Pierrot et al. (1973) |
| - (1998) | |
| R. Pierrot |
| R. Pierrot |
| R. Pierrot | |
| - (1998) | |
| - (1998) |
| R. Pierrot |
| |
| |
| Meisser et al. (2008) |
| - (1998) |
| - (1998) |
| |
| - (1998) |
| R. Pierrot |
| MAURY (S) +1 other reference |
Gabon | |
| Lheur et al. (2001) |
Germany | |
| Weiß (1990) |
| Walenta (1992) |
| Walenta (1992) | |
| Habel et al. (1994) |
| www.mineralienatlas.de (n.d.) |
| Lorenz (2004) |
| Dill et al. (2013) |
| Hans-Jürgen Haas collection |
| Weiß (1990) |
| Bald +1 other reference | |
| Weiß (1990) |
| in the collection of Joachim Esche | |
| Dill et al. (2010) +1 other reference | |
| Martin et al. (1994) |
| Wittern (2001) |
| Lapis 30 (7/8) |
| Herrmann et al. (2007) |
| Weisbach (1877) +2 other references |
| Tröger (2006) +1 other reference |
| Matt Wall |
| Wittern (2001) | |
Japan | |
| Hayashi & Nagashima (1965) |
Madagascar | |
| Behier (1959) |
| Behier (1960) |
Niger | |
| |
Poland | |
| Mochnacka K. 1975: Mineralizacja skał ... +2 other references |
| Lis et al. (1986) | |
| Syczewski et al. (2023) |
Portugal | |
| LNEG - Laboratório Nacional de Energia ... |
| LNEG - Laboratório Nacional de Energia ... |
| LNEG - Siorminp database information |
| Palache et al. (1951) |
| LNEG |
| LNEG/Siorminp database +1 other reference |
| Mineralien Atlas |
| |
Russia | |
| Kovalev et al. (2017) |
South Korea | |
| Jeong et al. (1999) |
Spain | |
| Desor (07/2020) |
| Menor et al. (2010) |
Tajikistan | |
| Chernikov et al. (1997) |
USA | |
| Austin (1964) +1 other reference |
| Granger (1959) |
| Granger (1959) +1 other reference |
| Granger (1959) |
| Troxel et al. (1957) +1 other reference |
| Eckel et al. (1997) |
| Eckel et al. (1997) | |
| Meschter (1953) +3 other references |
| Jensen et al. (2012) |
| Januzzi et al. (1976) |
| Tom Loomis website |
| USGS: Geological Survey Circular 359 |
| Page et al. (1956) +3 other references |
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Streuberg Quarry, Bergen, Vogtlandkreis, Saxony, Germany