Never used set of 12-oz Le Creuset rainbow mugs! Minor defect on blue mug, see last photo. -Premium stoneware is designed for everyday use -Colorful glaze is nonporous, non-reactive and resistant to chips, scratches and stains -Virtually nonstick glazed surface easily releases food for quick clean-up, and resists cracking and crazing -Superior heat retention keeps food warm or cold for serving -Safe for freezer, oven, microwave, broiler, dishwasher and metal utensils