A contribution to understanding the complex nature of peisleyite
- Creators
- Mills, S. J.
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Ma, C.
- Birch, W. D.
Abstract
The type specimen of peisleyite has been reinvestigated by a combination of scanning electron microscopy, electron probe microanalysis (EPMA) and synchrotron powder X-ray diffraction. Morphological investigation showed that mats of peisleyite crystals, individually <3 μm across, are intergrown with wavellite veinlets to form the white cryptocrystalline material that is typical of 'peisleyite'. New EPMA data (mean of 12 analyses) gave the empirical formula of peisleyite as (Na_(1.69)Ca_(0.18))_(Σ1.87)(Al_(9.04)Fe_(0.03))_(Σ9.07)[(P_(6.28)S_(1.38)Si_(0.25))O_4]_(Σ7.91)(OH)_(6.66)·27.73H_2O, or ideally Na_2Al_9[(P,S)O_4]_8(OH)_6·28H_2O. The associated wavellite was found to be F-rich. Synchrotron powder data were indexed and refined and gave the following unit cell: P1, a = 9.280(19), b = 11.976(19), c = 13.250(18) Å, α = 91.3(1), β = 75.6(1), γ = 67.67(1)º, V = 1308(5) Å3 and Z = 4. These data are significantly different to those reported in the original description of peisleyite.
Additional Information
© 2011 The Mineralogical Society. Received 03 August 2011; Accepted 28 October 2011. Referees Igor Pekov and Jiri Sejkora provided helpful comments on the manuscript and these are greatly appreciated. The collection of synchrotron data was undertaken at the Australian National Beamline Facility at the Photon Factory, Tsukuba, Japan, with support from the Australian Synchrotron Research Program, which is funded by the Commonwealth of Australia under the Major National Research Facilities Program. The SEM and EPMA analyses were carried out at the Caltech Geological and Planetary Sciences Division Analytical Facility, which is supported in part by NSF Grant EAR-0318518 and the NSF MRSEC Program under Grant DMR-00800065. John Bosworth is thanked for taking the photograph of the type specimen.Attached Files
Published - Mills2011p16818Mineral_Mag.pdf
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Additional details
- Eprint ID
- 28975
- Resolver ID
- CaltechAUTHORS:20120125-153336279
- Australian Synchrotron Research Program
- Commonwealth of Australia
- NSF
- EAR-0318518
- NSF MRSEC Program
- DMR-00800065
- Created
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2012-01-25Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field