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The fire of a diamond: What is it and why is it important?

You may have heard of the 5 Cs of a diamond, but have you heard about the fire of a diamond?

When shopping for a diamond, there is a lot to consider, and having that knowledge could be the difference between choosing an average stone over an outstanding one.

The fact that there is so much to learn about diamonds is what makes them so fascinating, and we love teaching people all about them, which is why we have created this small guide, outlining everything you need to know about the fire of a diamond!

What exactly is it?

The fire of a diamond doesn’t mean it is literally on fire, but rather is a reference to the colourful flashes of light that the stone diffuses whilst under light. It’s otherwise known as ‘light dispersion’ as this is an accurate description of how the colourful flashes are formed. Arguably, the fire is one of the biggest key contributors to a diamond’s beauty.

What affects a diamonds fire?

Whilst most diamonds have a fire, there are a few factors which affect how visible the fire is. This is where the importance of some of the 5 Cs crops up again.


The cut of a diamond refers to its overall shape, style, proportions and symmetry. It’s argued that the cut has the biggest impact on the fire, as it ultimately determines the diamond’s interaction with light. It’s often the case that the greater the cut grade, the more visible the fire will be. Cut grades range from deep cut, well cut, to shallow cut. Ideally, diamonds should be well cut for maximum fire. This is simply to do with the angles in which light brightly reflects off. If a diamond is cut too shallow or too deep, light will not reflect directly out the top.


Generally, the lower the clarity of a diamond, the less powerful the fire and sparkle in the stone will be. A diamond with poor clarity would have small imperfections on the surface that are visible to the naked eye, meaning light will be unable to enter inside the diamond and reflect out. Diamonds with a higher number of inclusions can often look dull and lackluster.


Typically, diamonds with less colour allow more light to pass through, so, the whiter the diamond, the greater the light dispersion. So, referring to the diamond colour guide below, a grade D, E or F diamond would give off the very best fire.


Light affects light. From sunlight to artificial light, not all lighting is the same, and diamonds can respond differently to different lights and environments. A diamond’s fire may not be so vibrant in dimly lit environments, as opposed to brighter and more direct light.

How to keep the fire burning

Even though your diamond might not look dirty, that doesn’t mean you should avoid regularly cleaning it. The importance of cleaning diamonds is often undermined but cleaning is what ultimately keeps them sparkling and the fire alive. The fire in your diamond will soon fade as the stone surface becomes dirtier and inclusions become more visible, making it difficult for light to enter and reflect. Cleaning diamonds is really quite simple. We recommend soaking it in a gentle degreasing solution once or twice a week to help keep it squeaky clean.


The fire of a diamond is just as important as other attributes, like brilliance and scintillation. As well as contributing to the overall beauty of your diamond, the fire also contributes to the quality of it.

Our highly skilled team of jewellers are always on hand to help you find the perfect diamond with a stunning fire!

Visit our boutiques in Glasgow or Aberdeen to discover our beautiful collection of diamond jewellery, from unique diamond pendants to stunning diamond rings. You can browse a selection of our diamond jewellery online here, but these items only represent a small selection of our in store stock.