corundum, treatments.6, gems

Crowningshield reports on sapphires subjected to X-ray bombardment and the resulting changes observed in their color. The note discusses irradiation as a cause of altered coloration in corundum and the gemological implications of such treatment, particularly the need to distinguish artificially induced color from natural coloration. As part of the Gem Trade Laboratory’s continuing series on unusual or noteworthy stones submitted for examination, the report documents experimental or treated sapphires encountered by the laboratory and draws attention to irradiation as a factor that must be considered when examining sapphire color.