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MINERAL CLASSIFICATION / SYSTEMATIK der MINERALE

           based on E.H. Nickel & M.C. Nichols (2009), H. Strunz & E.H. Nickel (2001),
           revised by Thomas Witzke (2022)



4. OXIDES, HYDROXIDES
(Oxides, Hydroxides, V[5,6]-Vanadates, Arsenites, Antimonites, Bismutites, Sulfites, Selenites, Tellurites, Iodates)


4.G: Uranyl Hydroxides


4.GA. Sheets with mainly UO2(O,OH)5 pentagonal bipyramides
 
4.GA.005. Compreignacite group
 
Compreignacite K2(UO2)6O4(OH)6·7H2O orth., Pnmn FOTO IMA 1964-026
Agrinierite K2Ca(UO2)6O6(OH)4·5H2O orth., Cmmm IMA 1971-046

Structure: sheets of edge-sharing UO2(O,OH)5 pentagonal bipyramides, based on the α-U3O8 type.


 
4.GA.010. Protasite
 
Protasite Ba(UO2)3O3(OH)2·3H2O mon., Pn IMA 1984-001

Structure: sheets of edge-sharing UO2(O,OH)5 pentagonal bipyramides, based on the α-U3O8 type.


 
4.GA.015. Becquerelite group
 
Becquerelite Ca(UO2)6O4(OH)6·8H2O orth., Pn21a FOTO G
Billietite Ba(UO2)6O4(OH)6·8H2O orth., Pn21 G

Structure: sheets of edge-sharing UO2(O,OH)5 pentagonal bipyramides, based on the α-U3O8 type.
Becquerelite: the layers of UO2(O,OH)5 bipyramides are connected by Ca in 7-fold coordination, 4 water, 2 oxygen from one uranyl layer and 1 oxygen from the next uranyl layer.
The arrangement of the cations is different in Becquerelite and Billietite.


 
4.GA.020. Masuyite
 
Masuyite Pb(UO2)3O3(OH)2·3H2O mon., Pn G

Structure: sheets of edge-sharing UO2(O,OH)5 pentagonal bipyramides, based on the α-U3O8 type.


 
4.GA.025. Richetite
 
Richetite (Fe,Mg)xPb8.6(UO2)36O36(OH)24·41H2O tric., P1 G

Structure: sheets of edge-sharing UO2(O,OH)5 pentagonal bipyramides, based on the α-U3O8 type.


 
4.GA.030. Schoepite group
 
Schoepite (UO2)8O2(OH)12·12H2O orth., P21ca A
Metaschoepite (UO2)8O2(OH)12·10H2O orth., Pbna FOTO G
Paraschoepite UO3·2-xH2O orth., Pbca Q

Structure: sheets of edge- and corner-sharing pentagonal UO2(O,OH)5 bipyramides.
Paraschoepite is possibly a mixture of Metaschoepite, Paulscherrerite and Ianthinite.


 
4.GA.035. Fourmarierite
 
Fourmarierite Pb1-xO3-2x(UO2)4(OH)4+2x·4H2O orth., Bb21m FOTO G

Structure: Schoepite type sheets of edge- and corner-sharing pentagonal UO2(O,OH)5 bipyramides.


 
4.GA.040. Kroupaite
 
Kroupaite KPb0.5(UO2)8O4(OH)10·10H2O orth., Pbca IMA 2017-031

Structure: Schoepite type sheets of edge- and corner-sharing pentagonal UO2(O,OH)5 bipyramides.


 
4.GA.045. Bobfinchite
 
Bobfinchite Na[(UO2)8O3(OH)11]·10H2O orth., Pbcn IMA 2020-082

Structure: Schoepite type sheets of edge- and corner-sharing pentagonal UO2(O,OH)5 bipyramides.


 
4.GA.050. Leesite
 
Leesite K(H2O)2(UO2)4O2(OH)5·3H2O orth., Pbca IMA 2016-064

Structure: Schoepite type sheets of edge- and corner-sharing pentagonal UO2(O,OH)5 bipyramides.


 
4.GA.055. Vandendriesscheite group
 
Vandendriesscheite Pb1.6(UO2)10O6(OH)11·11H2O orth., Pbca G
Metavandendriesscheite Pb(UO2)7O8·12H2O orth. G

Structure: Vandendriesscheite type sheets of edge-sharing pentagonal UO2(O,OH)5 bipyramides.


 
4.GA.060. Gauthierite
 
Gauthierite KPb(UO2)7O5(OH)7·8H2O mon., P21/c IMA 2016-004

Structure: Gauthierite type sheets of edge-sharing pentagonal UO2(O,OH)5 bipyramides.


 
4.GA.065. Ianthinite
 
Ianthinite [U4+2(UO2)4O6(OH)4(H2O)4]·5H2O orth., P21cn G

Structure: sheets of edge- and corner-sharing tetragonal U4+O2(O,OH,H2O)4 and pentagonal UO2(O,OH)5 bipyramides, based on the β-U3O8 type. The sheets are connected via interlayer water (Burns et al., 1997, MRS Online Proceeding Library Archive 465, 1193-1200).


 
4.GA.070. Rameauite
 
Rameauite K2Ca(UO2)6O8·9H2O mon., C2/c FOTO IMA 1971-045

Structure: sheets of edge- and corner-sharing tetragonal UO2(O,OH)4 and pentagonal UO2(O,OH)5 bipyramides, based on the β-U3O8 type.


 
4.GA.075. Spriggite
 
Spriggite Pb3(UO2)6O8(OH)2·3H2O mon., C2/c IMA 2002-014

Structure: sheets of edge- and corner-sharing tetragonal UO2(O,OH)4 and pentagonal UO2(O,OH)5 bipyramides, based on the β-U3O8 type.


 
4.GA.080. Shinkolobweite
 
Shinkolobweite Pb1.25[U5+(H2O)2(U6+O2)5O8(OH)2](H2O)5 orth., Imm2 IMA 2016-095

Structure: sheets of edge- and corner-sharing tetragonal UO2(O,OH)4 and pentagonal UO2(O,OH)5 bipyramides, based on the β-U3O8 type.


 
4.GA.085. Curite
 
Curite Pb3+x[(UO2)4O4+x(OH)3-x]2·2H2O orth., Pnam FOTO G

Structure: sheets of edge- and corner-sharing tetragonal UO2(O,OH)4 and pentagonal UO2(O,OH)5 bipyramides. Pb between the sheets in 10- and 12-fold coordination to oxygen (Taylor et al., 1981, Journ. Inorganic and Nuclear Chemistry 10, 2419-2423).


 
4.GA.090. Sayrite
 
Sayrite Pb2(UO2)5O6(OH)2·4 H2O mon., P21/n IMA 1982-050

Structure: sheets of edge- and corner-sharing tetragonal UO2(O,OH)4 and pentagonal UO2(O,OH)5 bipyramides. Pb2+ and H2O are between the sheets (Plasil, 2019, Z. Krist. 234, 733-738).


 
4.GA.095. Wölsendorfite
 
Wölsendorfite Pb7(UO2)14O19(OH)4·12 H2O orth., Cmcm G

Structure: sheets of tetragonal UO2(O,OH)4 and pentagonal UO2(O,OH)5 bipyramides. Pb2+ and H2O are between the sheets (Plasil, 2020, Bull. Min. Petro. 28, 322-330).



 
 
4.GB. Heteropolyhedral sheets of UO2(O,OH)5 pentagonal bipyramides with other polyhedra
 
4.GB.005. Vandenbrandeite
 
Vandenbrandeite Cu(UO2)(OH)4 tric., P1 FOTO G

Structure: dimers of edge-sharing UO2(O,OH)5 pentagonal bipyramides, connected by dimers of edge-sharing heavily distorted Cu(O,OH)6 octahedra to form sheets. The sheets are connected by sharing apical oxygens from U pentagonal bipyramides and Cu octahedra.


 
4.GB.010. Uranosphaerite
 
Uranosphaerite Bi(UO2)O2(OH) mon., P21/n FOTO G

Structure: heteropolyhedral sheet of edge- and corner-sharing UO2(O,OH)5 pentagonal bipyramides and Bi(O,OH)4 polyhedra (Hughes et al., 2003, Can. Min. 41, 677-685).


 
4.GB.015. Iriginite
 
Iriginite [(UO2)Mo2O7(H2O)2]·H2O orth., Pcam FOTO G

Structure: heteropolyhedral sheets of UO2(O,OH)5 pentagonal bipyramides and distorted MoO5(H2O) octahedra. The sheets are linked together by interlayer water via hydrogen bonds (Krivovichev & Burns, 2000, Can. Min. 38, 847-851).


 
4.GB.020. Umohoite
 
Umohoite [(UO2)MoO4(H2O)]·H2O tric., P1 FOTO G

Structure: heteropolyhedral sheets of chains of edge-sharing UO2(O,OH)5 pentagonal bipyramides, connected by distorted MoO4(H2O)2 octahedra. The sheets are linked together by interlayer water via hydrogen bonds (Krivovichev & Burns, 2000, Can. Min. 38, 717-726).


 
4.GB.025. Baumoite
 
Baumoite Ba0.5[(UO2)3O8Mo2(OH)3](H2O)3 mon. IMA 2017-054

Structure: heteropolyhedral sheets of clusters of 5 edge-sharing UO2(O,OH)5 pentagonal bipyramides, forming chains by sharing corners of two bipyramides from different clusters. The chains are connected by dimers of distorted Mo(O,OH)6 octahedra. The interlayer is occupied by Ba and H2O. Baumoite shows an incommensurable modulated structure (Elliot et al., 2019).



 
 
4.GC. Sheets with UO2(O,OH)6 hexagonal bipyramides
 
4.GC.005. Studtite group
 
Studtite (UO2)O2(H2O)2·2H2O mon., C2/m (?) G
Metastudtite (UO2)O2(H2O)2 orth., Immm IMA 1981-055


 
4.GC.010. Clarkeite
 
Clarkeite Na(UO2)O(OH)·nH2O trig., R3m FOTO G



 
 
4.GD. Heteropolyhedral sheets of UO2(O,OH)6 hexagonal bipyramides with other polyhedra
 
4.GD.005. Mourite
 
Mourite [(UO2)Mo5+2Mo6+3O10(OH)10] tric., P1 A

Structure: heteropolyhedral sheets of UO2(O,OH)6 hexagonal bipyramides and Mo(O,OH)6 octahedra.



 
 
4.GE. Other structures
 
4.GE.005. Deloryite
 
Deloryite Cu4(UO2)Mo2O8(OH)6 mon., C2/m IMA 1990-037

Structure: sheets of edge-sharing Cu(O,OH)6 octahedra. The sheets are linked by columns, built up of alternating pseudotetragonal UO6 bipyramides and pseudotrigonal MoO5 bipyramides. Two MoO5 bipyramides form [Mo2O8] dimers by sharing edges. Deloryite is chemically and crystallographically related to derriksite, Cu4(UO2)(SeO3)2(OH)6 (Pushcharovsky et al., 1996, J. of Alloys and Compounds 239, 23-26).


 
4.GE.010. Holfertite
 
Holfertite (UO2)1.75Ca0.25TiO4·3H2O trig., P3 IMA 2003-009


 
4.GE.015. Carlosbabosaite
 
Carlosbabosaite (UO2)2Nb2O6(OH)2·2H2O orth., Cmcm IMA 2010-047



 
 
4.GF. Unknown structures
 
4.GF.005. Paulscherrerite
 
Paulscherrerite (UO2)(OH)2 mon. IMA 2008-022


 
4.GF.010. Heisenbergite
 
Heisenbergite (UO2)(OH)2·H2O mon., P212121 (?) IMA 2010-076


 
4.GF.015. Calciouranoite group
 
Calciouranoite (Ca,Ba,Pb)(UO2)2O3·5 H2O (?) IMA 1973-004
Metacalciouranoite (Ca,Ba,Pb)(UO2)2O3·2 H2O (?) IMA 1971-054
Bauranoite Ba(UO2)2O3·4-5 H2O (?) FOTO IMA 1971-052



 
 

G = Grandfathered minerals: original description preceded the establishment of the CNMNC in 1959, and generally regarded as a valid species
A or IMA No. = Minerals approved by the CNMNC
Rd = Redefinition of the mineral approved by the CNMNC
Rn = Renamed with approval by the CNMNC
Q = Questionable mineral


© Thomas Witzke (2022)


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