SW-110 OysterCone 6 oxidation: Oyster is a variegated cream brown glaze that exhibits gray purple undertones and breaks brown. Cone 10 reduction: Color changes to a variegated brown cream. Increased movement. TIP: If your kiln fires cool, the glaze finish may be brown. An iridescent finish may be achieved by re firing or if your kiln fires hot. If you like Green Tea and Capri Blue combos, then try oyster because these three glazes are in the same glaze family.