Mineralogy of Halloysite from Suryun, Korea
Abstract
The halloysite in Suryun area, Seongju-Gun, Kyeongsang Buk-do-Korea, occurs as a distinctive kaolin mineral and has formed as a weathering product of feldspar in late Precambrian anorthositic rocks.
X-ray diffraction studies showed that the halloysite occurs naturally as a IOAO or hydrated form which on exposure to atmospheric conditions transformed to 7,40 or dehydrated form. The stability of interlayer water shows variation from sample to sample due to particle size. Scanning electron microscopy displayed that the halloysite occurs in tabular form growing in aggregates or in bundles in weathered plagioclase feldspar. Under transmission electron microscope the tubes show variable dimensions. Electron microprobe analyses show slight substitution of Al for Si in tetrahedral site of halloysite structure.
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