The old bricks were named after the place of origin: Waalsteen, originating from the surroundings of the river Waal. The old ice stones are from the many old stone factories on the IJssel. The raw material for all of the above brick is clay. The clay was often river clay from the floodplain. The clay type largely determines the properties of the final product. Iron-bearing clay gave the ice brick a red color after baking and calcareous clay more of a yellow color: the familiar yellow ijssel stones or yellows. A cubic stone is characterized mainly by its size. It is one of the smallest old masonry bricks available in the Netherlands. Because an old ice cube is hand-formed, the dimensions always differ slightly.