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Diamond Education:
Brilliance, Fire & Scintillation

A diamond reflecting light in a dark room

A flash of radiance. A shimmer of light. A twinkle that catches the eye. When it comes to fine jewelry, nothing dazzles quite like a diamond. These rare and beautiful gems are renowned for their sparkling allure. At the heart of their signature look are three qualities that help define their visual appeal – brilliance, scintillation, and fire. These qualities are dependent upon how a given diamond interacts with light, which in itself is dependent on a myriad of factors.

Understanding the interplay of brilliance, scintillation, and fire is crucial in appreciating the beauty of a diamond. In this article, we’ll discuss these three qualities, how they are achieved, and why they matter.

Brilliance: A Shine That Captivates

Close-up of a silver diamond ring in a man's hand

Brilliance is probably the most recognized quality of a diamond – it’s basically the initial white shine of light you see when the stone sits still.

This white reflection is the result of the diamond’s light play – or how it interacts and refracts light within its crystal lattice.

The quality of the diamond’s cut is paramount here – for a high degree of brilliance, the diamond has to be cut excellently, in a way that allows the maximum amount of light to be reflected back to the viewer’s eye, minimizing light leakage or “waste”. Shallow or deep cut diamonds in these circumstances leak too much light – which leads to a low degree of brilliance.

Albeit not as influential as the cut of a diamond, there are a few other factors that also influence the brilliance of a given stone:

Shape: Different diamond shapes (such as round brilliant, princess, or emerald cut) interact with light in different ways, and in doing so they affect Brilliance. Some shapes can enhance a diamond’s brilliance by maximizing light reflection, while others might emphasize fire and scintillation.

Clarity: Diamonds with a superior clarity grading have fewer imperfections that disrupt light play within its crystal lattice. Without these imperfections, light is allowed to reflect unimpeded, enhancing the overall amount of light reflected from the stone.

Color: Albeit not as influential as a diamond’s cut, the color of a diamond can also have an impact on its brilliance. When a diamond has more color, our perception of the white light reflected back by it can be affected by the presence of its hue. Generally speaking, colorless diamonds (D-F) are more easily perceived as “pure prisms” that reflect back white light with minimal presence of colors.

Scintillation: Dynamic Beauty

Scintillation refers to the patterns of light and dark observed when a diamond is moving.

Whereas brilliance deals with the visual beauty of a stone at rest, scintillation deals with the diamond’s beauty during movement. It can be described as the patterns of light and dark that are observed as a diamond is viewed dynamically – when either the observer, the light source, or the diamond itself is moving. It’s the characteristic that gives diamonds that lively appearance. The signature sparkle that is known to captivate across a room.

Diving down deeper, scintillation can be broken down into two parts: flash scintillation, and fire scintillation.

Both characteristics deal with diamonds being observed dynamically: flash scintillation refers to the white light patterns that are observed, and fire scintillation refers to the rainbow color patterns that are observed. Note that these rainbow colors are the result of white light being bent and dispersed into different wavelengths as it goes through the diamond.

Like with brilliance, a diamond’s scintillation is heavily dependent on the quality of its cut. For a high degree of scintillation, extreme care and skill are required to cut the diamond in a way so that its facets are optimized to reflect light while minimizing light leakage. This is to ensure that the diamond’s light play is efficient, in that all the light that enters the diamond doesn’t go unused.

For ideal cuts like these, large quantities of raw stone may be required to be sacrificed in the pursuit of an optimal cut. It’s akin to Michelangelo carving out a masterpiece out of a large slab of marble. Where perfection of cut is needed, sometimes sacrificing large amounts of raw materials is required. Along with the skill and expertise of the cutter, this sacrifice of carats is also the reason why ideal cut diamonds can be so expensive.

Fire: A Display of Color

Diamond being held by tweezers on a dark background

Diamond fire refers to the multitude of colors observed when white light is dispersed upon entering a diamond.

Similar to prisms, diamonds refract and bend white light. This process causes the white light, which comprises various wavelengths, to be ‘separated.’ Each color, characterized by a unique wavelength, is reflected at different angles – allowing them to be seen individually.

A diamond’s fire is the characteristic that allows you to see the “rainbow” colors under different lighting conditions. Like with real rainbows, the full potential of a diamond’s ability to refract light into its constituent colors is only fully revealed under specific lighting conditions. If there isn’t an ample amount of white light, there won’t be much fire since there won’t be much white light to be dispersed by the diamond.

That being said, a diamond’s ability to disperse light into its colorful components is greatly influenced by its cut. A well-cut diamond can enhance the fire, making it more pronounced and visible, regardless of the environment.

Balancing it All

While the traditional 4Cs of Diamonds are all factors that are crucial to consider when selecting a stone, brilliance, fire & scintillation are another set of characteristics to appreciate when selecting a stone.

Even though each factor is important, the magic of these three optical qualities is seen when they work together. It’s when brilliance, fire, and scintillation are in harmony with each other where we can see that signature look of a diamond – a bright shine, a myriad of colors, and an unmistakable sparkle.

Three diamonds indicating brilliance, fire and scintillation on awhite background
Fig 1. The classic shine and sparkle of a diamond comes from the combination of its brilliance, scintillation, and fire
Three diamonds indicating brilliance, fire and scintillation on a white background
Fig 1. The classic shine and sparkle of a diamond comes from the combination of its brilliance, scintillation, and fire

Even though each factor is important, the magic of these three optical qualities is seen when they work together. It’s when brilliance, fire, and scintillation are in harmony with each other where we can see that signature look of a diamond – a bright shine, a myriad of colors, and an unmistakable sparkle.

When selecting a diamond, it’s important to consider all elements of the stone in question. While certifications and grades can help guide you, it’s only by seeing the stone in person can you decide if it’s the right choice for you. Observe how it looks under different lighting conditions. Pick it up and move it under different lights. Walk around it in the showroom. Like with fingerprints, each diamond is different, and each will have a different cut, clarity, carat, and color, and each will have a different degree of fire, brilliance, and scintillation.

The trick here is to find a stone that fits with you – both visually and financially. A diamond’s beauty is subjective, so the most important thing to consider is how it makes you feel.

Armed with all this information, we understand that selecting the right stone can still be a daunting task. If you’re in the San Diego area, we invite you to our showroom where our team can help you in choosing the right stone. With over 40 years of expertise under our belt, and a GIA graduate gemologist on staff, we stand by to give you the world class jewelry experience that we are known for.