Berlepsch, P., Armbruster, T., Brugger, J., Criddle, A. J., Graeser, S. (2003) Tripuhyite, FeSbO4, revisited. Mineralogical Magazine, 67 (1) 31-46 doi:10.1180/0026461036710082
Reference Type | Journal (article/letter/editorial) | ||
---|---|---|---|
Title | Tripuhyite, FeSbO4, revisited | ||
Journal | Mineralogical Magazine | ||
Authors | Berlepsch, P. | Author | |
Armbruster, T. | Author | ||
Brugger, J. | Author | ||
Criddle, A. J. | Author | ||
Graeser, S. | Author | ||
Year | 2003 (February) | Volume | 67 |
Page(s) | 31-46 | Issue | 1 |
Publisher | Mineralogical Society | ||
DOI | doi:10.1180/0026461036710082Search in ResearchGate | ||
Mindat Ref. ID | 243409 | Long-form Identifier | mindat:1:5:243409:8 |
GUID | 0df5d017-5c2a-40c1-b4db-1be3e0ecd79e | ||
Full Reference | Berlepsch, P., Armbruster, T., Brugger, J., Criddle, A. J., Graeser, S. (2003) Tripuhyite, FeSbO4, revisited. Mineralogical Magazine, 67 (1) 31-46 doi:10.1180/0026461036710082 | ||
Plain Text | Berlepsch, P., Armbruster, T., Brugger, J., Criddle, A. J., Graeser, S. (2003) Tripuhyite, FeSbO4, revisited. Mineralogical Magazine, 67 (1) 31-46 doi:10.1180/0026461036710082 | ||
Abstract/Notes | AbstractThe exact nature of tripuhyite remains controversial more than 100 years after the first description of the mineral. Different stoichiometries and crystal structures (rutile or tri-rutile types) have been suggested for this Fe-Sb-oxide. To address these uncertainties, we studied tripuhyite from Tripuhy, Minas Gerais, Brazil (type material) and Falotta, Grisons, Switzerland using single-crystal and powder X-ray diffraction (XRD), optical microscopy and electron microprobe analysis.Electron microprobe analyses showed the Fe/Sb ratios to be close to one in tripuhyite from both localities. Single crystal XRD studies revealed that tripuhyite from the type locality and from Falotta have the rutile structure (P42mnm, a = 4.625(4) c = 3.059(5) and a = 4.6433(10) c= 3.0815(9) Å, respectively). Despite careful examination, no evidence for a tripled c parameter, characteristic of the tri-rutile structure, was found and hence the structure was refined with the rutile model and complete Fe-Sb disorder over the cationic sites in both cases (type material: R1 = 3.61%; Falotta material: R1 = 3.96%). The specular reflectance values of type material tripuhyite and lewisite were measured and the following refractive indices calculated (after Koenigsberger): tripuhyite nmin = 2.14, nmax = 2.27; lewisite (cubic) n = 2.04.These results, together with those of 57Fe and 121Sb Mössbauer spectroscopy on natural and synthetic tripuhyites reported in the literature, indicate that the chemical formula of tripuhyite is Fe3+Sb5+O4 (FeSbO4). Thus, tripuhyite can no longer be attributed to the tapiolite group of minerals of general type AB2O6. A comparison of the results presented with the mineralogical data of squawcreekite suggests that tripuhyite and squawcreekite are identical. In consequence, tripuhyite was redefined as Fe3+Sb5+O4 with a rutile-type structure. Both the proposed new formula and unit cell (rutile-type) of tripuhyite as well as the discreditation of squawcreekite have been approved by the Commission on New Mineral and Mineral Names (CNMMN) of the International Mineralogical Association (IMA). |
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