Mortars make it possible to create effects of materials and reliefs, in particular for the realization of funds. They are preferably worked with a knife. Artist Acrylics Pumice Mortar is a mortar based on acrylic polymer and finely crushed pumice stone. It offers the eye a fine material composed of small black particles for fine-grained material effects. It can be used pure or mixed with acrylic colors. Semi-matte finish.