EXAMINING A DIAMOND

摘要

In order to determine whether a blue-to-green diamond (1) has been artificially irradiated or ion bombarded to change its colour, it is irradiated with light of 633 nm wavelength in order to stimulate the emission of luminescence, and luminescence from about 680 to about 800 nm is detected using a confocal microscope (3) and a spectrometer (8) as the focal plane (9) is scanned vertically through the diamond (1). A rapid decrease in luminescence with increase in depth indicates natural irradiation whilst a more rapid decrease indicates ion bombardment. Alternatively, in order to determine whether a diamond (1) is a natural/synthetic doublet, it is irradiated with radiation of 325 nm wavelength in order to stimulate the emission of luminescence, and luminescence from 330 to 450 nm is detected. An abrupt change in luminescence with increase in depth indicates that the diamond is a natural/synthetic doublet.