Uranium tiles have been used in the ceramics industry for many centuries, as uranium oxide makes an excellent ceramic glaze, and is reasonably abundant. The uranium ore itself was considered a waste product and taking advantage of this newly abundant resource, the tile and pottery industry had a relatively inexpensive and abundant source of glazing material. Vibrant colors of orange, yellow, red, green, blue, black, mauve, etc. were produced, and some 25% of all houses and apartments constructed during that period (circa 1920–1940) used bathroom or kitchen tiles that had been glazed with uranium.
The use of uranium in ceramic glazes ceased during World War II when all uranium was diverted to the Manhattan project and didn’t resume until 1959. In 1987, NCRP Report 95 indicated that no manufacturers were using uranium-glaze in dinnerware.
10 minute measurement with a High Purity Germanium (HPGe) radiation detector.