Cone 6: Shipwreck is an aquamarine gloss glaze that contains an iron crystal. As the crystal melts, a small iron speck appears. The glaze appears mysterious like underwater footage. Cone 10: Color darkens. TIP: SW-212 Peacock is the base glaze.For a lighter crystal effect, you may try applying two coats of SW-212 Peacock with a third coat of SW-54 Shipwreck.