A natural phenomenon
Approximately one in three diamonds will glow under ultraviolet light, a natural phenomenon known as fluorescence. The vast majority of these stones have blue fluorescence of varying strength, though a very small percentage fluoresce in other colours, including green, yellow and red. In most cases, fluorescence is caused by the presence of nitrogen as a trace element impurity in diamond.
Some diamonds with “very strong” fluorescence can have a “milky” or “oily” look to them. These rare stones are known as “overblues.” A study by the GIA found that with the exception of “overblues” and yellow fluorescent diamonds, fluorescence has little effect on transparency.
Generally it isn’t advisable to buy strongly fluorescent diamonds, but in certain instances it might be a good idea – for example, if your budget limits you to a diamond with a slight yellowish tint. In this case, some blue fluorescence might actually cancel out the yellow and make the diamond appear whiter than it actually is.
You can learn more about how diamonds are graded at our diamond grading page.
Call us on 020 3468 7917 or come and see us in person at our showroom close to Bond Street station, London. You’ll be able to discover our stunning collection, speak to our experts one-on-one and explore the option of creating your very own bespoke ring. We aim to respond to appointment booking emails within 1 hour.