Kaolin is mined on the island of Belitung and Bangka located in the JavaSea north of Jakarta (Fig. 31). The majority of the mining is on Belitung.The kaolins there are residual and altered from porphyritic granite(Murray et al., 1978). The mineralogical and chemical changes in thealtered granite from the surface down to the fresh granite show that thefeldspars alter to kaolinite and halloysite; the biotite alters to hydrobiotiteand then to vermiculite followed by smectite; and the quartz is unalteredexcept for solution pitting. The kaolin which is mined is comprised of vermicularkaolinite stacks, and plates along with some halloysite (Fig. 32).
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