Stories from Physics for 11-14 14-16
The colour of gemstones is sometimes altered by exposing them to gamma rays. Colourless quartz will become smoky and pale whilst colourless diamonds can be turned blue, green, red and yellow through irradiation. Only a year after Antoine-Henri Becquerel’s discovery of radioactivity in 1896, William Crookes buried a diamond in radium bromide powder for several months and discovered it turned a bluish-green colour. The effect occurs due to carbon atoms being knocked out of the crystal lattice by the passage of gamma rays.