AMACO-Mexican Pottery: Self-Hardening Clay. A durable; self- hardening clay in moist form perfect for all methods of modeling including sculpting; coiling; pinching; slabwork; and wheel through. The rich red terra cotta color is similar to Mexican and Indian pottery with little or no decoration necessary. It comes moist and ready to use with no kiln or oven-firing necessary. This package contains 5lbs of red clay. Non-toxic and conforms to ASTM D4236. Made in USA.