Why Do Diamonds Sparkle? Diamond Brilliance, Fire and Scintillation

Diamond Fire & Sparkle

What gives a diamond its sparkle?

The process of diamond cutting transforms a diamond from its original form. From an insignificant crystal in the ground, the true beauty of a diamond comes from the expertise of the diamond cutter.

The diamond cutting process reveals the true hidden beauty of a diamond. From the rough crystal to the final faceted gemstone, the final result changes the passage of light passing through the diamond. At the same time, light reflects from the stone.

A significant part of a diamond’s value results from the cutting process. The cut and proportions of a diamond can influence value by as much as 40 per cent. For this reason, great time and effort go into cutting a diamond to release not only beauty but its value at the same time.

Most people refer to fire, brilliance and scintillation. But few people understand the difference between each of these terms.

In the following video, a round brilliant cut diamond sparkles with fire, brilliance and scintillation in a tension setting of our Unity ring design.

Light refraction and reflection in diamonds

The passage of light through a diamond slows as it passes through the matrix of carbon crystal.

Light bends as it passes from one medium to another—an effect referred to as refraction.

As this light travels through the diamond, it strikes another surface within the stone, causing part of the light to be reflected back.

The proportions of a diamond change the way light passes through a diamond. A well-proportioned diamond reflects most light back internally. Light passes back to the eye through the table facet. The result we refer to as brilliance. Conversely, a poorly proportioned diamond leaks light. As a result, poorly cut diamonds appear far less brilliant by comparison. Diamonds sparkle owing to the effect of brilliance with additional factors.

What is diamond fire?

Light passing through a diamond bends. As light passes through a diamond it splits into different colours. We see the same effect in water droplets when a rainbow forms. Also, when light passes through a prism.

This means that a beam of white light going into a diamond comes out as a spectrum of different colours. When we see the colours of the spectrum in a diamond, we call this fire. 

Some diamond cuts exhibit greater fire than others. For example, Emerald-cut diamonds give greater fire but less brilliance. In contrast, brilliant-cut diamonds demonstrate greater brilliance and less fire.

Diamond sparkle and diamond fire

A diamond splits white light into colours of the spectrum, referred to as ‘fire.’

What is scintillation?

The effect of light and movement creates scintillation. Scintillation is the play of white and coloured flashes of light seen when the diamond is viewed in motion.  Viewable with the naked eye, scintillation is the life of the diamond.

We divide scintillation into flash scintillation and fire scintillation. Flash scintillation comes from bright flashes of light dancing across the polished facets of a diamond. When this effect throws flashes of colour, we refer to this as fire scintillation.

The quality of a diamond’s polish results adds or subtracts from the scintillation. An excellent polish assists in the reflection of light from each facet of the diamond.

The effect of fire, brilliance and scintillation on a diamond

The combined effect of fire, brilliance and scintillation gives a diamond life.

Together, the beauty of a diamond comes from the “across-the-room-sparkle.”

Few gemstones have this overall effect. We should remember that without light, diamonds have no brilliance, fire or scintillation. Light brings a diamond to life with an effect that few gemstones achieve.

How to keep the sparkle of your diamond

The attraction of grease and dirt to a diamond causes the loss of diamond sparkle. The build-up of hand creams and oils on the back of a diamond ring causes significant loss of sparkle. Remember to clean your diamond regularly using the Dazzlestik to restore sparkle.

Mark Johnson

About Mark Johnson

Mark attended Liverpool University and went on to pursue a career in the diamond industry. After more than a decade working in polished diamonds, Mark moved to the Isle of Wight where he launched Serendipity Diamonds. He works most days from their busy Ryde showroom, photographing jewellery and writing for the Serendipity Diamonds website.

Mark Johnson

About Mark Johnson

Mark attended Liverpool University and went on to pursue a career in the diamond industry. After more than a decade working in polished diamonds, Mark moved to the Isle of Wight where he launched Serendipity Diamonds. He works most days from their busy Ryde showroom, photographing jewellery and writing for the Serendipity Diamonds website.