Carlosbarbosaite

(UO2)2Nb2O6(OH)2 · 2H2O
IMA status
  • Approved
IMA symbol
Cbb
IMA approved
2010
Also known as
  • Carlosbarbosaiet
  • IMA2010-047

Where it forms, where it's found

Type locality
Jaguaraçu pegmatite
  1. Jaguaraçu
  2. Minas Gerais
  3. Brazil

-19.6499°, -42.7464°

7recorded occurrences
Source · OpenStreetMap

Radioactivity

Physical

Transparency
Transparent · Translucent
Colour
Cream to pale yellow
Streak
Yellowish white
Density
4,713 g/cm³

Optical

UV response
None.

Crystallography

Crystal system
Orthorhombic
Space group
#50
Cell parameters
a = 14.150(6) Å · b = 10.395(4) Å · c = 7.529(3) Å
Ratio a:b:c
1 : 0.735 : 0.532
Type-locality form

Long flattened lath-like crystals with a very simple orthorhombic morphology. The crystals are elongated along [001], flattened on (100) and up to 120 μm long and 2–5 μm thick.

Crystal structure

Chemical composition

Constituent elements
Mass composition breakdown
ElementAtoms At. mass g/mol Mass g/molMass share
92UUraniumUranium2238.029476.058
53.38%
8OOxygenOxygen1415.999223.986
25.11%
41NbNiobiumNiobium292.906185.812
20.83%
1HHydrogenHydrogen61.0086.048
0.68%
Total891.904100.00%

Mass share = atoms × atomic mass ÷ molar mass × 100

From IMA formula

Synonyms

  • Carlosbarbosaiet
  • IMA2010-047

In other languages

German
Carlosbarbosait · IMA 2010-047
Italian
carlosbarbosaite
Portuguese
Carlosbarbosaita

Classification

Strunz
10th ed.

4.GB.75

  • 4OxidesClass
  • 4.GUranyl HydroxidesDivision
  • 4.GBWith additional cations (K, Ca, Ba, Pb, etc.); with mainly UO2(O,OH)5 pentagonal polyhedraGroup
  • 4.GB.75CarlosbarbosaiteSpecies

Literature, links & citation

Citations
  1. 2011Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2011) New minerals and nomenclature modifications approved in 2010, CNMNC Newsletter No 7. Mineralogical Magazine, 75 (1) 27-31 doi:10.1180/minmag.2011.075.1.27 DOI: 10.1180/minmag.2011.075.1.27
  2. 2012Atencio, D., Roberts, A. C., Cooper, M. A., Filho, L. A. D. Menezes, Coutinho, J. M. V., Stirling, J. A. R., Venance, K. E., Ball, N. A., Moffatt, E., Chaves, M. L. S. C., Brandão, P. R. G., Romano, A. W. (2012) Carlosbarbosaite, ideally (UO2)2Nb2O6(OH)2·2H2O, a new hydrated uranyl niobate mineral with tunnels from Jaguaraçu, Minas Gerais, Brazil: description and crystal structure. Mineralogical Magazine, 76 (1) 75-90 doi:10.1180/minmag.2012.076.1.75 DOI: 10.1180/minmag.2012.076.1.75
  3. 2014(2014) Carlosbarbosaite. Handbook of Mineralogy. Mineralogical Society of America
  4. 2023Lira, Raúl, Parra, Francisco J., Biglia, Marco E., Morello, Orquídea, Guereschi, Alina B. (2023) Genesis and New Mineral Chemistry Data of Carlosbarbosaite, a Potential U and Nb Ore Source from Miarolitic-, A-Type Granites and NYF Pegmatites of the La Chinchilla Pluton, Velasco Ranges, La Rioja, Argentina. The Canadian Journal of Mineralogy and Petrology, 61 (5) 927-964 doi:10.3749/2300008DOI: 10.3749/2300008
Cite this entry
@misc{mineral2026,
  author    = {Mineral Index editorial board},
  title     = {Carlosbarbosaite — Mineral Index},
  year      = {2026},
  url       = {https://mineralindex.org/minerals/carlosbarbosaite-41099},
  note      = {Accessed 2026-05-11}
}