Caldasite

Caldasite
Zircon-favas

Composition
Primary	Zircon (ZrSiO4), Baddeleyite (ZrO2)
Secondary	Uranium (as triuranium octoxide [U2O3])

Caldasite (Portuguese: Caldasito, German: Zirkonglaskopf, Spanish: Caldasita) is a rare uraniferous ore of zirconium found in the Poços de Caldas massif, located in the states of Minas Gerais and São Paulo, Brazil.

It is most often found as a dark gray, very dense, hard rock. It also appears as a friable brown substance.

The massif is an alkaline complex, formed by a large intrusion during the mid-Cretaceous. The ore is a result of hydrothermal alteration of the nepheline-syenitic rocks; it has also been weathered out and concentrated in paleoplacer deposits.

Further reading

• Brown, A.E.P. (1972). Aproveitamento do Zircônio e do Urânio de um Mineral Complexo de ZrSiO₄ e ZrO₂ (Caldasito), da Região de Poços de Caldas, Estado de Minas Gerais, Brasil [Reclaiming Zirconium and Uranium from a ZrSiO₄–ZrO₂ Compound Mineral (Caldasite), Poços de Caldas Region, Minas Gerais, Brazil] (PDF) (Master's) (in Portuguese). São Paulo Polytechnic University. Retrieved January 27, 2016.
• Brown, A.E.P.; Costa, E.C. (1972). "Processing of a uraniferous zirconium ore". 4073530. {{cite journal}}: Cite journal requires |journal= (help)
• Curtius, A.J. (1975). "Radioactive disequilibria in Brazilian caldasite". Inorganic and Nuclear Chemistry Letters. 11 (12): 841–845. doi:10.1016/0020-1650(75)80111-5. ISSN 0020-1650. Retrieved January 27, 2016.
• Derby, O.A. (January 1887). "On Nepheline-Rocks in Brazil, with Special Reference to the Association of Phonolite and Foyaite". Quarterly Journal of the Geological Society. 43 (1–4). London: 457–473. doi:10.1144/GSL.JGS.1887.043.01-04.35. Retrieved January 28, 2016.
• Forman, J.M.A.; Angeiras, A.G. (26–29 November 1979). "Poços de Caldas and Itataia: two case histories of uranium exploration in Brazil" (PDF). Proceedings of an advisory group meeting on case histories of uranium exploration. Advisory Group Meeting. Vienna: International Atomic Energy Agency. pp. 99–139. ISBN 92-0-141081-6. IAEA-AG-250/14. Retrieved 2016-01-28.
• Franco, R.R.; Loewenstein, W. (1948). "Zirconium from the region of Poços de Caldas" (PDF). American Mineralogist. 33 (3–4): 142–151. Retrieved January 27, 2016.
• Laznicka, P. (1985). Empirical Metallogeny, Depositional Environments, Lithologic Associations and Metallic Ores. Phanerozoic Environments, Associations and Deposits. Elsevier. p. 1531. ISBN 978-0-444-59756-4. Retrieved 28 January 2016.
• Takenaka, L.B.; Lana, C.; Scholz, R.; Nalini Jr., H.A.; de Abreu, A.T. (October 2015). "Optimization of the in-situ U–Pb age dating method via LA-Quadrupole-ICP-MS with applications to the timing of U–Zr–Mo mineralization in the Poços de Caldas Alkaline Complex, SE Brazil". Journal of South American Earth Sciences. 62: 70–79. doi:10.1016/j.jsames.2015.04.007.
• Tolbert, G.E. (1966). The Uraniferous Zirconium Deposits of the Poços de Caldas Plateau, Brazil. USGS Bulletin. doi:10.3133/b1185C. 1185-C. Retrieved 30 January 2016.
• Ulbrich, H.H.G.J. (1984). A Petrografia, a Estrutura e o Quimismo de Nefelina Sienitos do Maciço Alcalino de Poços de Caldas MG-SP [Petrography, Structure and Chemistry of the Nepheline Syenite Poços de Caldas Alkaline Massif] (Habilitation) (in Portuguese). Instituto de Geociências, University of São Paulo. Retrieved 2016-01-28.
• Ulbrich, H.H.G.J.; Vlach, S.R.F.; Ulbrich, M.N.C.; Kawashita, K. (March 2002). "Penecontemporaneous syenitic-phonolitic and basic-ultrabasic- carbonatitic rocks at the Poços de Caldas alkaline massif, SE Brazil: Geologic and geochronologic evidence". Revista Brasileira de Geociências (Now Brazilian Journal of Geology). 32 (1): 15–26. ISSN 2317-4692. Archived from the original on 2016-03-11. Retrieved 8 February 2016.
• Ulbrich, H.H.G.J.; Vlach, S.R.F.; Demaiffe, D.; Ulbrich, M.N.C. (2005). "Structure and origin of the Poços de Caldas Alkaline Massif, SE Brazil". In Comin-Chiaramonti, P.; Gomes, C.B. (eds.). Mesozoic to Cenozoic Alkaline Magmatism in the Brazilian Platform. São Paulo: Edusp/Fapesp. pp. 367–418. ISBN 978-85-314-0903-5. Retrieved 2016-01-30.