This glass bowl is made from sand containing uranium, which not only gives the glass its characteristic green colour, but makes it radioactive and strongly fluorescent. Uranium has long been used as a glass colourant, dating back to the first century AD. Uranium glassware was very popular in the early 20th century; however, production was curtailed when countries started conserving uranium supplies when the world entered the nuclear age during the Second World War. The rim of this particular bowl, which dates from around 1950 and comes from Australia, has been whitened by exposure to mercury. Explore uranium glass on the Institute of Making website: https://www.instituteofmaking.org.uk/materials-library/material/uranium-glass-bowl.