The Nascence of Clay Minerals

Abstract

It is a high honor to be invited to give this first Brindley Memorial Lecture. I view it as taking the first step on a ladder, to be followed by suceeeding talks that climb higher to the pinnacle that George Brindley erected for us in clay mineralogy. If George were with us, he would be sitting on the front row, as usual, keeping the speakers and audience "honest" in our deliberations. In turn, I would be privileged to ask him personally to enlighten us with his valued opinion on the many questions I will be asking in this talk.

Elucidating the crystal-chemistry of Jbel Rhassoul stevensite (Morocco) by advanced analytical techniques

“…The SEM micrographs, as well as EDX analysis results for the bulk clay sample, are presented in Figs 5 and 6. In the natural clay sample the particles have an automorphous, petalloid-like microstructure typical of smectite clay (Chamley, 1989;Keller, 1985;Wilson & Pittman, 1977). Petals are either present in the form of planar flakes or exhibit folded edges to produce a flowerlike structure (Figs 5a and b).…”

Mineralogy, Geochemistry and Utilization Study of the Madayi Kaolin Deposit, North Kerala, India

“…Trace amounts of smectite were identified in L5 (14 A) ( Figure 2B). The formation of smectite is favored by a microenvironment with poor drainage and hence minimum leaching conditions with relatively high metal ion concentrations (Keller, 1985). Gibbsite identified by the 4.84 A peak in L3, L5, L7, L9 and L11 indicates intense leaching in a strongly deionized environment under tropical climate (Vazquez, 1981) during desilication, i.e.…”

“…The residual kaolinite shows crystals with angular edges (Figures 6A and 6B), which suggest in situ formation. The irregular angular kaolinite edge is characteristic of actively growing crystals (Keller, 1985). Kaolinite grains were found at the edge of micaceous stacks or books suggesting the alteration of muscovite to kaolinite ( Figure 6B).…”

Geological, mineralogical and chemical characterization of Devonian kaolinite-bearing sediments for further applications in the ceramic (tiles) industry in La Paz, Bolivia

“…5), we could conclude that the studied material exhibits poor crystallinity. The composition, heterogeneity and the irregular angular edges (Keller 1985 ; Fig. 6a, b) suggest primary formation, which is characteristic of actively growing crystals as a result of the on-going weathering process and is an indication of in situ formation.…”