Research News: Chromism in Pink Diamonds

[The Australian Gemmologist, John Chapman - Rio Tinto Diamonds] Pink diamonds from Argyle have been known by polishers, laboratories and traders to exhibit a phenomenon of photochromism whereby their colour can be influenced by illumination of different lights and intensities. These influences are relatively short-lived and most conspicuous after illumination by short wavelength light of high intensity. This effect is particularly noticeable when using instruments to observe fluorescence, such as a DiamondView, which after use with Argyle pink diamonds results in a distinctively bleached or pale colouration.

Intensification of the colour can be achieved by subjecting a pink diamond to elevated temperature – thermo-chromism, while the colour can also change unpredictably during polishing – a phenomenon known as tribo-chromism. All these possible changes are temporary and the colour can be readily returned to an ‘ambient resting colour’.

Full article via Fancy Color Research Foundation