decay, until they reach a safe level of less than 1 nCi/g to 2.7 nCi/g depending on the country.

The first documented artificially irradiated gemstone was created by English chemist William Crookes in 1905 by burying a colorless diamond in powdered radium bromide. After having been kept there for 16 months, the diamond became olive green. This method produces a dangerous degree of long-term radioactive contamination and is no longer in use. Some of these