The geology and mineralogy of the Puramahoi kaolin deposits near Takaka, North-west Nelson, New Zealand, are described. The deposits form seams up to one metre thick in the deeply weathered Motupipi Coal Measures of Early Tertiary (Eocene) age. Examinations by XRD, IR, DTA, and EM show that the clay is composed largely of kaolinite and quartz with minor amounts of secondary 2M1mica, goethite, lepidocrocite, pyrite, and carbonaceous and amorphous siliceous material. Results show that the clay minerals are largely detrital although some authigenic kaolinite is present. Only two of the clay seams sampled are suitable for high quality ceramic ware. The presence of impurities restricts the use of the remainder unless treatment is carried out. Ellipsoidal pyrite nodules within the clay were also examined.