The domestic clays of Kishajmás and Bátaszék are highly formable, plastic clays originating from sedimentary rocks. Due to their high iron content their colour is reddish when fired. Owing to their calcium (lime) content they are not recommended to be fired at temperatures exceeding 1040 ºC because they tend to melt. The lime content of the clay originating from Hargita, Transylvania, is lower, therefore it can be fired at a higher temperature. The composition of the masses called Köztes white and Köztes red varies therefore these are recommended for hobby potters.