The brick has a red base, with colours ranging from orange-red, bright-red to violet. The red shades are obtained by using natural sands with varying baking colours. The darker shade on the facing brick is obtained by means of coal-sintering.
The facing brick (non-perforated) is sanded on five sides, and provided with an possible oblong sloping groove on one flat side. The structure is formed by a rough appearance with fine and irregular grooves in the sandy surface. The baking process is done in a gas-fired tunnel kiln under a slightly reducing atmosphere.