Metauranocircite
A valid IMA mineral species - grandfathered
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About Metauranocircite
Formula:
Ba(UO2)2(PO4)2 · 7H2O
Colour:
Greenish yellow, yellowish green
Lustre:
Resinous, Waxy, Greasy, Pearly
Hardness:
2 - 2½
Specific Gravity:
3.94
Crystal System:
Monoclinic
Member of:
Name:
Named meta-uranocircite in 1904 by Paul Gaubert for its dehydrated relationship to uranocircite, where 'meta-' indicated the dehydration as earlier done with meta-autunite. Renamed to meta-uranocircite-I by Walenta (1963). The first hyphen was removed in a 2008 renaming (Burke 2008). The suffix was dropped in 2022, giving metauranocircite.
Type Locality:
Isostructural with:
Meta-autunite Group.
Rapid dehydration of uranocircite in dry atmospheres at normal temperature results in metauranocircite (metauranocircite-I of Walenta, 1963).
Metauranocircite may be more common than realized because of its similar appearance to meta-autunite and other species.
Rapid dehydration of uranocircite in dry atmospheres at normal temperature results in metauranocircite (metauranocircite-I of Walenta, 1963).
Metauranocircite may be more common than realized because of its similar appearance to meta-autunite and other species.
Unique Identifiers
Mindat ID:
2665
Long-form identifier:
mindat:1:1:2665:5
Classification of Metauranocircite
The autunite-type sheet
The autunite-type sheet found in members of the meta-autunite group and shared with members of the autunite group.
IMA Classification of Metauranocircite
Approved, 'Grandfathered' (first described prior to 1959)
IMA status notes:
Renamed by the IMA
IMA Formula:
Ba(U6+O2)2(PO4)2(H2O)4·2H2O
First published:
1904
Type description reference:
8.EB.10
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.3.2
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+
19.11.21
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 |
|---|---|---|
| Murc-I | 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 Metauranocircite
Resinous, Waxy, Greasy, Pearly
Transparency:
Transparent, Translucent
Colour:
Greenish yellow, yellowish green
Streak:
Yellowish white
Hardness:
2 - 2½ on Mohs scale
Tenacity:
Very brittle
Cleavage:
Perfect
{001}
{001}
Density:
3.94 g/cm3 (Measured) 3.95 g/cm3 (Calculated)
Optical Data of Metauranocircite
Type:
Biaxial (-)
RI values:
nα = 1.610 nβ = 1.621 - 1.623 nγ = 1.622 - 1.623
Birefringence:
0.002
Max. Birefringence:
δ = 0.012 - 0.013
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:
High (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.
No measured or calculated 2V is on file for this mineral, so the value used here (23°) 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 (23°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Dispersion:
relatively strong
Optical Extinction:
X = c
Pleochroism:
Weak
Comments:
X = colorless
Y = Z = Pale canary yellow
Y = Z = Pale canary yellow
Chemistry of Metauranocircite
Mindat Formula:
Ba(UO2)2(PO4)2 · 7H2O
Element Weights:
Crystallography of Metauranocircite
Crystal System:
Monoclinic
Class (H-M):
2 - Sphenoidal
Space Group:
P21
Cell Parameters:
a = 6.943(2) Å, b = 17.634(6) Å, c = 6.952(2) Å
β = 90.023(7)°
β = 90.023(7)°
Ratio:
a:b:c = 0.394 : 1 : 0.394
Unit Cell V:
851.2 ų
Z:
2
Morphology:
Platy square crystals, also earthy.
Comment:
Pseudotetragonal metrics; twinned. Data for synthetic material.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 8.82 Å | (100) |
| 5.46 Å | (15) |
| 4.410 Å | (55) |
| 3.723 Å | (50) |
| 2.708 Å | (20) |
| 2.205 Å | (18) |
| 1.4621 Å | (18) |
Comments:
ICDD 36-407
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 21 : Chemically precipitated carbonate, phosphate, iron formations | |
| 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:
Sedimentary uranium deposits, granite pegmatites
Type Occurrence of Metauranocircite
Place of Conservation of Type Material:
State Museum for Mineralogy and Geology, Dresden, Germany.
Mining Academy, Freiberg, Germany.
Mining Academy, Freiberg, Germany.
Synonyms of Metauranocircite
Other Language Names for Metauranocircite
Relationship of Metauranocircite to other Species
Member of:
Other Members of Meta-autunite Group:
| Abernathyite | K(UO2)(AsO4) · 3H2O | Tet. 4/mmm(4/m2/m2/m) : P4/ncc |
| Arsenosabugalite | H0.5Al0.5(UO2)2(AsO4)2 · 8H2O | Tric. 1 : P1 |
| Chernikovite | (H3O)2(UO2)2(PO4)2 · 6H2O | Tet. 4/mmm(4/m2/m2/m) : P4/nmm |
| Lehnerite | Mn2+(UO2)2(PO4)2 · 8H2O | Mon. 2/m |
| Meta-ankoleite | K2(UO2)2(PO4)2 · 6H2O | Tet. 4/mmm(4/m2/m2/m) : P4/nmm |
| Meta-autunite | Ca(UO2)2(PO4)2 · 6H2O | Tet. 4/mmm(4/m2/m2/m) |
| Metaheinrichite | Ba(UO2)2(AsO4)2 · 8H2O | Mon. 2 : P21 |
| Metakahlerite | Fe2+(UO2)2(AsO4)2 · 8H2O | Tric. 1 : P1 |
| Metakirchheimerite | Co(UO2)2(AsO4)2 · 8H2O | Tric. 1 : P1 |
| Metalodèvite | Zn(UO2)2(AsO4)2 · 10H2O | Tet. 4/m : P42/m |
| Metanatroautunite | Na(UO2)(PO4)(H2O)3 | Tet. 4/mmm(4/m2/m2/m) : P4/ncc |
| Metanováčekite | Mg(UO2)2(AsO4)2 · 8H2O | Tet. 4/m : P4/n |
| Metarauchite | Ni(UO2)2(AsO4)2 · 8H2O | Tric. 1 : P1 |
| Metasaléeite | Mg(UO2)2(PO4)2 · 8H2O | |
| Metatorbernite | Cu(UO2)2(PO4)2 · 8H2O | Tet. 4/m : P4/n |
| Metauranospinite | Ca(UO2)2(AsO4)2 · 8H2O | Tet. 4/m : P42/n |
| Metazeunerite | Cu(UO2)2(AsO4)2 · 8H2O | Tet. 4/m : P42/n |
| Natrouranospinite | Na2(UO2)2(AsO4)2 · 5H2O | Tet. 4/mmm(4/m2/m2/m) : P4/nmm |
| Trögerite | (H3O)(UO2)(AsO4) · 3H2O | Tet. 4/mmm(4/m2/m2/m) : P4/nmm |
| Uramarsite | (NH4)(UO2)(AsO4) · 3H2O | Tet. 4/mmm(4/m2/m2/m) : P4/mmm |
| Uramphite | (NH4)2(UO2)2(PO4)2 · 6H2O | Tet. 4/mmm(4/m2/m2/m) : P4/nmm |
Common Associates
Associations Based on Photo Data:
| 9 photos of Metauranocircite associated with Quartz | SiO2 |
| 8 photos of Metauranocircite associated with Goethite | Fe3+O(OH) |
| 6 photos of Metauranocircite associated with Tridymite | SiO2 |
| 5 photos of Metauranocircite associated with Uranophane | Ca(UO2)2(SiO3OH)2 · 5H2O |
| 3 photos of Metauranocircite associated with 'Rhyolite' | |
| 3 photos of Metauranocircite associated with Thomsenolite | NaCa[AlF6] · H2O |
| 2 photos of Metauranocircite associated with Sklodowskite | Mg(UO2)2(SiO3OH)2 · 6H2O |
| 2 photos of Metauranocircite associated with 'Smoky Quartz' | SiO2 |
| 1 photo of Metauranocircite associated with Dewindtite | H2Pb3(UO2)6O4(PO4)4 · 12H2O |
| 1 photo of Metauranocircite associated with Uraninite | UO2 |
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 | Uranocircite | Ba(UO2)2(PO4)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 | 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) | 47.9205% | 11,980,125 | 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 Metauranocircite
Very fluorescent yellow-green in SW and LW UV.
Other Information
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 Metauranocircite
mindat.org URL:
https://www.mindat.org/min-2665.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 Metauranocircite
Reference List:
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
Nuffield, E. W., Milne, I. H. (1953) Studies of radioactive compounds: VI - Meta-uranocircite. American Mineralogist, 38 (5-6) 476-488
Pulou, Raymond (1957) Méta-uranocircite d'Entraygues (Aveyron) Bulletin de Minéralogie, 80 (1) 32-38 doi:10.3406/bulmi.1957.5132
Frondel, Clifford (1958) Systematic mineralogy of uranium and thorium. Bulletin 1064. US Geological Survey doi:10.3133/b1064 pp.211-215
Khosrawan-Sazedj, Fereshteh (1982) The crystal structure of meta-uranocircite II, Ba(UO2)2(PO4)2·6H2O. TMPM Tschermaks Mineralogische und Petrographische Mitteilungen, 29 (3) 193-204 doi:10.1007/bf01084642
Vochten, R. F., Van Haverbeke, L., Van Springel, K. (1992) Transformation of chernikovite into meta-uranocircite II, Ba(UO2)2(PO4)2.6H2O and study of its solubility. Mineralogical Magazine, 56 (384) 367-372 doi:10.1180/minmag.1992.056.384.09
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
Locock, A. J., Burns, P. C., Flynn, T. M. (2005) Structures of strontium- and barium-dominant compounds that contain the autunite-type sheet. The Canadian Mineralogist, 43 (2) 721-733 doi:10.2113/gscanmin.43.2.721 (synthetic meta-uranocircite I)
Burke, Ernst A. J. (2008) Tidying up mineral names: an IMA-CNMNC scheme for suffixes, hyphens and diacritical marks. The Mineralogical Record, 39 (2) 131-135
Localities for Metauranocircite
Showing 50 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.
Austria | |
| Brandstätter et al. (1990) +1 other reference |
| Aufschluss 1972 (SB) +1 other reference |
| Exel (1993) |
Brazil | |
| Atencio et al. (2004) |
| D Atencio & R Hypolito () |
| Fosfatos e Silicatos Secundários de ... | |
Canada | |
| Chatterjee (1977) |
Czech Republic | |
| Pauliš P. et al. (Kutna Hora, issue 1) |
| Jirásek et al. (2016) |
| Pauliš P. et al. (Kutna Hora, issue 1) |
| Pauliš P. et al. (Kutna Hora, issue 1) |
| Uranové minerály České republiky a ... |
Europe | |
| Pauliš P. et al. (Kutna Hora, issue 1) |
France | |
| |
| Lièvre et al. (2002) |
| Lièvre et al. (2002) |
| Lièvre et al. (2002) |
| J. Geffroy |
Gabon | |
| Lheur et al. (2001) +1 other reference |
Germany | |
| Walenta (1992) |
| Walenta (1992) |
| Walenta (1992) | |
| Lorenz (2004) |
| Dill et al. (2010) |
| Lapis 30 (7/8) |
| Hermann et al. (2006) | |
| Schnorrer-Köhler (1991) +1 other reference |
Niger | |
| www.cnncintl.com (2015) |
Poland | |
| Mochnacka et al. (2000) +2 other references |
| Syczewski et al. (2023) +1 other reference | |
| Lis et al. (1986) | |
| Syczewski et al. (2023) |
| Mochnacka et al. (2000) |
| Rewerski et al. (2014) +2 other references | |
Portugal | |
| LNEG info +1 other reference |
USA | |
| Holland et al. (1958) +3 other references |
| Granger (1955) +1 other reference | |
| Eckel et al. (1997) |
| Am Min (1957) |
| Jensen et al. (2012) |
| |
| Roberts et al. (1965) |
| Mineralogical Society of America - ... |
| Tom Loomis website | |
| Mineralogical Society of America - ... | |
| Smith et al. (2000) |
| Bullock (1981) |
| Luetcke (n.d.) | |
| Jerden (2001) |
| rruff.geo.arizona.edu (n.d.) |
Quick NavTopAbout MetauranocirciteUnique IdentifiersClassification IMA Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography X-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesRelationshipsCommon AssociatesStrunz-MindatRadioactivityFluorescence Other InformationInternet Links References Localities Locality List
Krunkelbach Valley Uranium deposit, Menzenschwand, St Blasien, Waldshut, Freiburg Region, Baden-Württemberg, Germany