Abstract: A decorative stone or tile, preferably for the fortification of sloping surfaces such as embankments, banks, or the like, which consists of parallel ribs and crosspieces extending at right angles to the ribs with several of the ribs projecting beyond the outer crosspieces and several crosspieces projecting beyond the outer ribs. The projecting ends of the ribs and crosspieces are provided with either grooves or tongues corresponding to the grooves. The grooves or tongues are formed respectively by boundary surfaces extending vertically to the stone surface and are arranged in an alternate pattern about the periphery of the stone or tile. At least one extension is provided between the projecting ends of the externally disposed ribs and crosspieces. The extension is shorter than the length of the projecting ends of the ribs and crosspieces. The extension includes an end face which extends parallel to the vertical plane in which the crosspieces and/or ribs extend.