Smooth, bright, vivid colors that allow you to create anything you can imagine. Crayon Rocks™ are great for line work, for blending, and for creating wide swaths of color. Developed by a special needs teacher, Crayon Rocks™ were designed to strengthen a child's tripod grip muscles, preparing fingers and hands for pen and pencil use. Crayon Rocks™ are made in America from natural soy wax, using American-grown soy beans and natural mineral colors. They are non-toxic and conform to CPSIA regulations.