Electron-Optical and Electron-Diffraction Study of a Disordered Structural State in the Transformation Goethitehematite

J. D. C. McConnell and J. Lima-de-Faria1
Dept. of Mineralogy and Petrology, Downing Place, Cambridge.
1Junta de Investigaçöes do Ultramar, Lisbon.

Summary: Previous X-ray observations by J. Lima-de-Faria and P. Gay on the transformation goethite-hematite indicate that in the process of state change at low temperatures, maxima of scattered X-ray intensity occur as satellites to strong and diffuse Bragg maxima due to hematite. These maxima define a repeat distance of about 32 Å. Corresponding satellite maxima have been observed using electron diffraction technique and satellite maxima flanking the direct beam (000) have been used to obtain a direct electron optical image of the disordered state at high magnification. Such photographs show a mainly regular fringe system with spacing of approximately 30 Å. Dislocation patterns were also observed.

Mineralogical Magazine; September 1961 v. 32; no. 254; p. 898-901; DOI: 10.1180/minmag.1961.032.254.04
© 1961, The Mineralogical Society
Mineralogical Society (www.minersoc.org)