Cone 6: Green Opal achieves a vibrant chartreuse gloss when fired. Lighter applications lead to a semi-opaque yellow-green; heavier applications see the formation of a green float. Cone 10: Color lightens; becomes more transparent. TIP: Darker clay bodies, such as buff and brown, display the phosphorescent qualities of Green Opal. On manganese bodies, Green Opal will interact with manganese bodies, creating interesting brown streaks. Thinner application will provide a glossy transparent finish. Thicker application will provide light green floating. Surface decoration will be visible under the glaze, but if you apply the glaze thick, it could blur your image. and pool into