Jewellery

Why Do Some Diamond Rings Sparkle More Than Others?

21 July 2026

Veronica Olszowska

Diamonds are the hardest known gemstones and yet they comprise the simplest composition, they are made of just one substance: pure, crystalline carbon. Diamonds are assessed using the Four Cs: colour, clarity, carat weight and cut. Together these characteristics determine a diamond's appearance, with cut having the greatest influence on sparkle.

Quick answer: The sparkle of a diamond is determined by the combination of its cut, clarity, colour and carat weight, known as the Four Cs. Of these, the cut has the greatest influence on brilliance, fire and scintillation, controlling how light enters and returns from the stone.

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How Does Clarity Affect Sparkle?

Clarity is important as it enables light to pass easily through a flawless or nearly flawless diamond, whereas natural inclusions block the passage of light and diminish the reflection and refraction of that light. In coloured stones the cut affects the hue so a fancy cut is more often used as the round brilliant cut can diminish the colour.

Why is Diamond Cut So Important?

An expertly cut diamond ensures that the play of light through the stone maximises the brilliance, fire and scintillation. Brilliance is defined as the light that is reflected off the facets of the stone, fire describes the dispersion of light into the individual colours of the light spectrum and scintillation gauges the flashes of light or sparkle seen when a diamond is moved.

The finish of a cut of diamond is divided into polish and symmetry. The polish denotes the quality of the surface of the stone; it may be perfect initially but over time it may become abraded with wear and so dull the sparkle of the stone. The symmetry is crucial as the position of the facets and the precision of their cut can enhance or diminish the potential sparkle of a stone.

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Why Do Round Brilliant Diamonds Sparkle More?

The Round Brilliant Cut is the most popular diamond cut and was developed by Marcel Tolkowsky in 1919 to maximise the return of light. The proportions and angles of the crown and table facets, coupled with the depth of the pavilion of the stone all contribute to the quality of the cut and the overall appearance of the stone. If the stone is cut with a shallow pavilion the light will pass through the bottom of the stone and reflections are lost. If the stone is cut too deep the light will reflect onto the opposite facet and leak out of the side of the stone. This can make the stone appear black at its centre.

Approximately three quarters of all diamonds sold are round brilliant cut diamonds, with 57 or 58 facets. Fancy cut describes any stone that is not round brilliant cut and these use a mixture of brilliant and step cuts.

Why is Cut the Most Important of the Four Cs?

The most important influence on the sparkle of a diamond can be said to be the cut. When a diamond is perfectly proportioned, whether in rings, earrings, necklaces or bracelets, the rays of light will refract towards the centre and then be reflected out through the top of the stone, creating the much-admired brilliance, fire, scintillance and sparkle.

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Frequently Asked Questions

A diamond sparkles because light enters the stone and is reflected back through the crown. The quality of the cut has the greatest influence on this process, while clarity, colour and carat weight also contribute to its appearance.

Brilliance is the white light reflected back from a diamond's facets. A well-cut diamond returns more light to the eye, creating a brighter appearance.

Fire describes the dispersion of white light into the colours of the spectrum, producing flashes of red, blue, green and other colours as the diamond moves.

Scintillation refers to the flashes of light and contrast seen when a diamond or the observer moves. It contributes to the lively sparkle associated with well-cut diamonds.

Round brilliant cuts typically require more of the original rough gemstone to be removed in order to achieve their ideal proportions. Their enduring popularity and exceptional light performance also contribute to higher prices.

The Round Brilliant Cut was specifically designed to maximise light return. Its carefully calculated proportions allow light to enter, reflect within the stone and return through the top, producing exceptional brilliance and fire.

Not necessarily. A well-cut smaller diamond will often appear brighter and more lively than a larger diamond with poor proportions.

Yes. Diamonds with fewer inclusions allow light to pass more freely through the stone, improving brilliance. However, cut generally has a greater effect on sparkle than clarity alone.

Why Do Some Diamond Rings Sparkle More Than Others?

Discover our Jewellery Department

How Does Clarity Affect Sparkle?

Why is Diamond Cut So Important?

Jewellery

Why Do Round Brilliant Diamonds Sparkle More?

Why is Cut the Most Important of the Four Cs?

Veronica Olszowska

Frequently Asked Questions

What makes a diamond sparkle?

What is brilliance in a diamond?

What is fire in a diamond?

What is scintillation?

Why are round brilliant cuts often more expensive?

Why do round brilliant diamonds sparkle more?

Does a bigger diamond sparkle more?

Does clarity affect sparkle?