See the quality of these stoneware bowls and mugs. Reactive glass, textured surface that is lightly speckled. Microwave and Dishwasher safe. • Size: DIA3.5 x H1in, 2 oz. • Material content: Stoneware. • Care instructions: Dishwasher & microwave safe. • The nature and beauty of reactive glaze is that each piece is unique. There may be slight variations in color, texture and finish to each perfectly imperfect item.