Beyond the 4Cs: The Importance of Lustre, Overtone and Fluorescence
Diamonds
Beyond the 4Cs: The Importance of Lustre, Overtone and Fluorescence
The Gregory Standards ensures that our diamonds are carefully examined by eye, and not relying on a diamond’s certified characteristics alone.
22 May 2020 5 minute read

LUSTRE

The Gregory Standards ensures that our diamonds are examined for their lustre and transparency, by carefully examining each diamond by eye, and not relying on a diamond’s certified characteristics alone. This natural characteristic is often overlooked, but can directly affect the brilliance, dispersion and scintillation of a diamond.

 

Below are two round brilliant cut diamonds, they have identical carat weight, colour, clarity. Their other characteristics, including cut, polish symmetry & fluoresce grades are also identical, and both diamonds are accompanied by a reputable international certificate. You could be fooled into thinking that these two diamonds would look identical, however, the natural transparency of the diamond on the left is far superior to the transparency of the diamond on the right, making it a more brilliant, lively diamond.

At Gregory Jewellers we source our diamonds based on their physical beauty, rather than relying on certified characteristics alone.

 




Fluorescence can be described as a phenomenon that occurs when a diamond is exposed to invisible Ultra-Violet light (UV).

 

About 30% of all diamonds in the world are fluorescent.

 

This characteristic is generally noted on the accompanying certification, and although fluorescence generally cannot be seen in a boutique or retail store environment – it can dramatically affect a diamond’s beauty and value. Some diamonds that have a medium to very strong fluorescent grading can appear to look milky or foggy under natural sunlight (which contain natural ultraviolet light).

 

The Gregory Standard details the strength and colour of any natural fluorescence. The fluorescence scale varies by strength – from: none, faint, medium, strong, and very strong.

 

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