Cone 6: Copper Float glaze is a rich and complex midrange glaze with hues varying from reds, to coppers to gun metal blacks. Predominate coloration is a dark rusty red. The surface is satin-matte when fired to cone 5 or 6. Cone 10: Finish flattens. Color changes to a warm brown with some copper mottling. TIP: One coat will produce dark, greenish tones, thicker coats will add greens. Thickest applications will result in metallic red hues.