Designed with the potter in mind. Achieve Cone 10 reduction effects without using a reduction gas kiln or firing at high temperatures. Potter's Choice glazes add fluid colors and effects to smooth or textured ware, with optimal results at Cone 5 or 6. Suitable for stoneware and porcelain clays. For best results, read label carefully. Lead-free and food safe. Pint jar. Midnight blue. AP Seal, non-toxic.