Cone 06: Night Sky is a glossy, denim blue glaze with a dark gray stain. It has large and medium light blue crystals. Cone 6: Base glaze changes to brown/green and breaks over texture; crystals melt. Enhanced mobility. Surface issues may occur. TIP: This glaze WILL move. Take care when using on vertical pieces reduce glaze thickness towards the bottom third to minimize run-off. This glaze will pinhole at three coats.