Amazing Condition Handmade by Chehalem Mountain Pottery Matte Blue Gray Stoneware Ceramic Steampunk Mug Holds About 14 oz. 5.5" High 5" Length with Handle I got the information about this mug from their Etsy site Handmade of white stoneware with an inordinate amount of attention to detail and finished with a satin-matte black glaze on the outside. Glazes on the inside were layered to make it look like this mug used to contain old motor oil. The hex washer head screw heads on the outside are paired with nuts on the inside (so it wouldn't fall apart, ya know). T here is no metal in this mug. It's all ceramic. There is only one of these as The artist purposely tries to make each mug unique. Microwave-able and dishwasher safe!