Dioctahedral vermiculite was prepared from muscovite by treating with molten LiNO₃ after White (1958), then boiling in an AlCl₃ solution and aging at pH 5.0 for 5 days. The prepared vermiculite was tested by X-ray diffraction method, differential thermal analysis, infrared absorption spectroscopy and electron micrography.
The basal spacing of 14Å in the prepared vermiculite was decreased to 10.7 Å by heating and to 11Å by boiling in N KOH-N KCl (Brown, 1953), but hardly changed by glycerol sorption and by boiling with N NH₄NO₃ (Walker, 1949). The results show good agreement with those obtained by Brown (1953) for dioctahedral vermiculite.
Differential thermal curves of the prepared vermiculite showed an endothermic peak near 500°C and an exothermic peak at 900°C, which were absent in the original muscovite. The indicated hydration in the interlayer position of the mineral was also supported from infrared absorption spectroscopy.
Morphological differences between the muscovite and the prepared vermiculite were hardly observed on electron micrographs.

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A kaolin mineral was obtained from vermiculite under various conditions of acid environments. Mineralogical properties of thus obtained kaolin mineral are similar to those of well-crystallized natural kaolinite. Some considerations were made on the mechanism of the transformation of vermiculite

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