Great art starts with great products. Louis Prang developed child-safe art products that uphold the highest standards of quality in materials and color. These standards are maintained today in a comprehensive line of Prang art products for both children and professionals. Prang Hygieia is superior chalk made from 95 percent pure calcium carbonate and free of foreign materials that work their way into the board surface causing scratching, streaking and pitting. They feature a round stick which fits most chalk chucks. Hygieia is available in white, yellow, and assorted colors and is AP certified non-toxic. Be bold, color your world, and discover Prang power!