Stone Art is a refined paper pulp with a specific composition that when combined with Powertex makes an air-dried clay which will keep in an air-tight container for up to six months. Discover the versatility of this fabulous texture medium for creating structure and realistic stone effects in your artwork. Easy to use. Excellent for painting or sculpture. Allow to dry for three weeks, then varnish with two coats of Easy Varnish (or similar) before placing outside.