A mold device and method for producing a rough texture on all or a portion of the outward exterior surfaces of masonry block units. The device of the present invention is a mold having one or more cavities, open at the top and the bottom, with a rigid support platform or sheet across the bottom, to hold the masonry mixture in place until discharged through the bottom of the mold. On a portion of the interior sidewalls of the mold, are substantially vertical ribs extending from the interior surface, creating voids in the compacted mixture. An extension or “stripper” unit extends inwardly along the base of the portion of the interior wall containing the vertical ribs. A top plate configured to fit removably within the interior walls of the mold cavity is provided to compact the masonry mixture and to push the masonry unit out of the mold and simultaneously clean the mold. As the masonry unit is pushed from the mold, the stripper extension or bar moves a portion of the compacted partially hardened masonry material, filling in the voids created and left by the ribs, and creating a textured surface.