Antique stoneware, pottery or earthenware that is 100 years old or older can possess radioactive materials. Stoneware, particularly orange-red plates and other dining pieces, derived their color from the inclusion of radionuclides, a naturally occurring radioactive nuclide or atom with an unstable nucleus that was added to the glaze.
Stoneware glazes that were used prior to the 1960s often contain uranium and potassium 40, which release radiation. It is very important that these earthenware and stoneware dishes not be used to hold food or drinks as food that comes in contact with the surface is not safe for consumption. Red-orange Fiestaware plates are good examples of the harmful radioactive glaze. A single plate, manufactured from 1936 to 1973, can contain 4.5 grams of uranium.
Antique stoneware and pottery can be used safely for interior design and decoration. Crocks and Spongeware water coolers are examples of multi-use pieces of antique stoneware that can be used safely to provide elegant and beautiful décor.
Not all antique stoneware contains radioactive properties. Bauer stone and other pottery brands from the late 1800s, as well as Camark, Pigeon Forge, Shawnee, Van Briggle and Ransbottom Pottery, do not contain any harmful properties. If a person collects antique stoneware, it is best to use caution and research the specific piece of pottery before using it to serve anyone.