Mustard Seed Yellow Mustard Seed Yellow Stonecast Churchill Super Vitrified Crockery Buy the Churchill Stonecast range of super vitrified mustard seed yellow crockery. Beautifully hand decorated with a speckled and stippled edge so each piece is unique.Designed for hospitality environments. Microwave and dishwasher safe. Fully glazed base with a superior glaze finish. BS4034, BS8654, BS12875.