Diamond Fluorescence

What is Diamond Fluorescence?

Fluorescence is only detectable under strong ultraviolet light and occurs in varying degrees of colour. The fluorescence of diamonds tends to manifest as a blue colour. In rare cases, the presence of fluorescence exhibits itself as a yellow colour, however this is more commonly found in coloured stones.

Fluorescence in diamonds is very rare; whilst cut, clarity, carat and scarcity of the diamond colour all increases the price of a diamond; fluorescence actually decreases the price of a diamond, just as an inclusion does. Despite this, fluorescence in diamonds can make them appear whiter and closer to colourless. Blue fluorescent colouring can actually improve the colour of a diamond by a grade or two, whilst reducing the cost.

The Negative and Positive Impact of Diamond Fluorescence

Diamond fluorescence is generally considered fine in diamonds from grades G to J as it improves the colouring and reduces the cost. Fluorescence in a diamond from grades D - F can make the diamond appear opaque and poorly polished and these negative attributes can outweigh the positive benefits. However, even with distinct or strong fluorescence this is extremely rare.

Fluorescence found in diamonds from grades K to M can increase the price of the diamond; largely due to the fact that these diamonds possess a faint yellow colour – in this instance the blue fluorescence counter balances the yellow colour and makes the diamond appear whiter. The level of fluorescence in a diamond should be reported on the diamond certification. Levels of fluorescence that occur in diamonds are described on the GIA diamond certification report as: None, Faint, Medium, Strong and Very Strong.

Although diamond fluorescence can be seen as a negative attribute and can decrease the cost of the diamond, this rarely affects its beauty or indeed its desirability.

Diamonds that have been graded as ‘Faint’ will not be negatively affected, largely due to the fact that it can be very hard to detect. Even for ‘Medium’ graded diamonds, the effects of fluorescence are highly unlikely to detract from the beauty of the stone.

The majority of ‘Faint’ and ‘Medium’ graded diamonds can confidently be used to create truly stunning pieces of jewellery.