Abstract
Studies on minerals featuring the 2: 1 to 1: 1 layer transformation such as 2: 1-2: 1: 1 intergrades and 2: 1/1: 1 mixed layer minerals were briefly reviewed. The identity of vermiculite-chlorite as one of those minerals was examined in the light of recent information obtained from studies on clay minerals in Korean Ultisols and Alfisols (Red-Yellow Soils). It was indicated that vermiculite is associated with kaolin mineral but not with polymer hydroxy-Al ions and that the mineral would be called an intergradient vermiculite-kaolin mineral. A possible structure of the new intergradient mineral was inferred to be that in which most vermiculite layers eachpartially transform into double kaolin layers.
