Uranium glass had uranium added to it before melting to create colors. Typically, pieces were made with low levels of uranium, anywhere from trace amounts to 2%. Some pieces contained up to 25%.
The uranium was added for the fluorescent effect it created. It soon became incredibly popular and started to be manufactured across Europe and North America. Peak popularity was from 1880’s to 1920’s. Production plummeted post WW2 since Uranium was in demand by the military.
Most uranium glass is decorative, tableware or household items, with many pieces looking like carnival glass. Uranium glass bowls are particularly popular. My mother in law owns a piece of Uranium glass. This is what it looks like under a black light.
HAPPY TRAILS, STEVE