Aspedamite

Aspedamite is a very rare mineral, one of two natural heteropolyniobates.[1] Its chemical formula (one of the possible formulas) is complex and shows the presence of essential vacancies: []12(Fe3+2Fe2+)Nb4(ThNb9Fe3+2Ti4+O42)(H2O)9(OH)3. Its structure (isometric, space group Im3) is the same as of the second known heteropolyniobate - menezesite.[2][3] Aspedamite is somewhat similar to another mineral from Norway, peterandresenite, which is a hexaniobate.[4]

References
  1. "Aspedamite: Aspedamite mineral information and data". Mindat.org. Retrieved 2016-03-04.
  2. Cooper, M.A., Abdu, Y.A., Ball, N.A., Černý, P., Hawthorne, F.C., and Kristiansen, R., 2012. Aspedamite, Ideally []12(Fe3+,Fe2+)3Nb4[Th(Nb,Fe3+)12O42]12{(H2O),(OH)}12, a New Heteropolyniobate Mineral Species from the Herrebøkasa Quarry, Aspedammen, Østfold, Southern Norway: Description and Crystal Structure. The Canadian Mineralogist 50, 793-804; DOI: 10.3749/canmin.50.4.793
  3. "Menezesite: Menezesite mineral information and data". Mindat.org. Retrieved 2016-03-04.
  4. "Peterandresenite: Peterandresenite mineral information and data". Mindat.org. Retrieved 2016-03-04.
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