Institution: | 1 Institute of Geosciences, Faculty of Science, Shizuoka University, Shizuoka 422, Japan 2 Department of Earth Sciences, Faculty of Science, Nagoya University, Chikusa, Nagoya 464, Japan |
Abstract: | Halloysite A, which is a weathering product of feldspar in granitic rocks and of matrix clay minerals in sand, takes the shape of long tubes. Halloysite B which is a weathering product of pyroclastic materials takes the shape of balls, nodules, scrolls or short tubes. Stability of the interlayer water of halloysite varies from sample to sample, but does not show a simple relation to these genetical types. Chemical analysis and ESR show that halloysite B contains more structural Fe than halloysite A. |