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kaolinitization (kaolinization) Hightemperature hydrothermal alteration (see HYDROTHERMAL ACTIVITY) and replacement of feldspars, to varying degrees, to form a fine-grained aggregate of the mineral kaolinite. Kaolinitization in granites can be so complete that the rock is reduced to a rotten, friable condition, quartz being the only mineral to survive the process unscathed. In this condition, the altered granite can be easily broken down by a highpressure water jet and the kaolinite settled out from suspension in settling pools to produce china clay (kaolin) concentrates. See also CHINASTONE.