With Crystals Glazes, color crystals move throughout the glaze during firing, creating a distinctively interesting appearance. Each result depends on the size of the crystal, slope of the piece and temperature of the fire. Mix without disturbing crystals. Apply 2 coats to cone 04 bisque. Mix in crystals in third coat. Avoid heavy crystal application near base. Glaze fire to cone 06. Water clean up. Non-Toxic. Click on the image to see the entire line.