Hostname: page-component-7b7567c8c-jswmv Total loading time: 0 Render date: 2026-11-15T09:33:05.489Z Has data issue: false hasContentIssue false

The Hinckley index for kaolinites

Published online by Cambridge University Press:  09 July 2018

A. Plançon
Affiliation:
CRSOCI and Université d'Orleans, 45100 Orleans, France
R. F. Giese
Affiliation:
Department of Geology, State University of New York, 4240 Ridge Lea Road, Amherst, NY 14226
R. Snyder
Affiliation:
New York College of Ceramics, Alfred University, Alfred, NY 14802, USA

Abstract

The (02,11) X-ray diffraction band from a low-defect kaolinite from Cornwall (Hinckley index HI = 1·22) was examined to determine the defect structure. No combination of interlayer translations and admixing of dickite layers accurately modelled the observed diffraction pattern. Calculated diffraction patterns which gave a good agreement with the shape, position, and intensity of the observed peaks, uniformly had inter-peak intensities which were too weak. By treating the kaolinite as a mixture of low-defect (HI = 1·76) and moderate-defect (HI = 0·29) kaolinites, the agreement between the observed and calculated patterns was improved substantially. The existence of a mixture of two kaolinites was also found for a number of low-defect samples (HI > 0·4) from Georgia and Cornwall, and may be of even wider occurrence. The HI, which is very sensitive to the inner-peak intensities, does not estimate the types or abundances of various structural defects (the classical “crystallinity”), but is related directly, in a non-linear fashion, to the proportions of the two kinds of kaolinite which are present in the sample.

Information

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1988

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Article purchase

Temporarily unavailable