Radioactive Residue (7.34)
All three of these irradiation methods do not leave any detectable radioactive residue in the stone after treatment. This was not always true. Shortly after Marie Curie discovered Radium and Polonium in 1898, Sir William Crookes exposed colorless diamond crystals to radium compounds for approximately one year. Although the experiment was a success, the dark green-colored hue it left was very shallow, and the treated diamonds were made radioactive. The radioactivity was dangerous, but it is believed that most of these stones have been removed from circulation.
