Everything in Nature has some imperfections and diamonds are no different that way. A diamond’s imperfections are natural as they formed inside the Earth. One such characteristic is the fluorescence in diamonds. This is not usually visible to someone unless the fluorescence is very obvious.

A diamond contains fluorescence when there is a variation or irregularity in its atomic structure. Some diamonds may appear to glow more than the others.

This process occurs naturally within the Earth as the diamonds are being formed. One cannot do anything to change or lessen the fluorescence in diamonds.

When traces of elements like nitrogen, boron or aluminium are found in diamonds, they cause the stones to fluoresce. The atomic structure of each element can change the fluorescent hue.

This characteristic is an important part of diamond education. Fluorescence is a blue glow in a diamond that is visible only under an ultraviolet (UV) light.

Diamond graders check diamonds under this UV light to check for fluorescence in diamonds. As far as fluorescence is concerned, blue is the most common colour in diamonds. Orange and yellow are the rarer fluorescent colours.

A diamond certificate always mentions if a diamond contains fluorescence or not. Sometimes, a diamond appears to be fluorescent even after the UV light source is removed. This is called phosphorescence.

The grading starts from None and goes up to Very Strong with Faint, Medium and Strong in the middle. Knowingly or unknowingly, consumers do purchase diamonds with some amount of fluorescence.

Some diamond graders believe that a slight blue fluorescence makes diamonds with a faint colour more attractive.

Since sunlight is also UV light, yellowish diamonds appear nearly colourless under the sun and therefore demand a higher price. The blue fluorescence downplays the colour in a stone.

In the case of colourless diamonds, fluorescence is an undesirable attribute. And so, diamonds between the clarity grades D to H look a little cloudy when they have fluorescence.

According to the Gemological Institute of America (GIA), not all diamonds fluoresce. Fluorescence is present in about 25% to 35% diamonds. This shows that while this attribute is not a very rare one, it is also not as common.

While buying a diamond, fluorescence plays an important role in diamond pricing. Just like all the other parameters of a diamond affect its pricing, fluorescence does too.

In most cases, it does not affect the appearance of a rock, unless seen under UV light. At other times, the stone may contain so much fluorescence that it appears milky or cloudy.

Such stones are not even pretty and hence cannot be sold too. It is obvious even to consumers that such stones lack the shine and brilliance.

Though there is no hard and fast rule for fluorescence in diamonds, some diamond jewellery brands prefer not to sell such stones. Of course, the consumer’s choice matters above all else but it is always better if they first know.