In the past, this word "Ceramic" was applied to dishes, made of clay, and to be cooked afterwards; but nowadays, this word comprises all products made of fictile clay and bat, such as brick, tile, clay pipe and all fire-proofs made of bat, vitreous china and various species of porcelain, as well as china-ware. This would make it inert and therefore will have no effect on pH, kH, gH etc.