Brilliance, Fire and Scintillation

Diamond Brilliance, Fire and Scintillation

Bottom Line Recommendations

  • The diamond brilliance, fire, and scintillation are affected most by the quality of the cut. The brilliance refers to the brightness of the diamond as you can see here. Without it, a diamond will appear dull.
  • Some diamond shapes are cut to maximize brilliance. These are called brilliant cuts. Others are cut to show the diamond’s luster. These are called step cuts.
  • Diamond fire refers to the white light that is separated into its seven visible colors. This gives a diamond its life. The more the diamond is able to display its fire, the better the quality of the cut. Take a look at this example here.
  • When buying your diamond, make sure that it is neither too deep nor too shallow. Either of these can cause light that enters the diamond to escape through the bottom. Find the perfect depth that optimizes light reflection.
  • Do not go below a good cut on the cut scale as a diamond below this grade will appear dull and will not have much brilliance, fire and scintillation as you can see here.

James Allen Diamonds

The best way to judge the appearance of a diamond is by observing 360-degree videos. We recommend buying from James Allen or the Blue Nile. They offer the best quality videos and images. You will not be able to tell how a diamond performs in the light by just using the diamond report.

In the diamond world, 3 terms prop up often in conversations whether you are choosing the perfect diamond for you or your partner or you are having an engaging conversation about a stone that you saw on someone’s finger.

Brilliance, fire, and scintillation are mentioned time and time again. Often people tend to use these terms interchangeably. To better understand what they mean, let’s take a closer look.

Diamond Brilliance

This is the white light that is emitted by the diamond. Without it, there would be no fire or sparkle. One of the main attractions of a diamond is how much it will sparkle when set in the light.

Before a diamond can emit such white light, it has to be mined from the earth as diamond rough. The skin is opaque. After it is removed, it reveals the clear stone underneath through cutting and polishing.

You can compare the diamond with a window. If the window is less clear or is misshapen, it will not let in light the same way as a clear window can.

If, however, the diamond has a good cut and is well polished, it will be super clear to let in as much light as possible.

The diamond’s cut and polish are therefore highly crucial to the brilliance of a diamond. Once the rough stone is taken from the ground, a cutter will determine how best to cut it to minimize wastage. He will also decide whether he will cut a step-cut diamond or a brilliant-cut diamond.

With the step cut, the stone will have fewer facets and the end goal is to make the stone as clear as possible. It is not the type of diamond that is renowned for brightness. That said the step cuts have plenty of fire.

That title goes to the brilliant-cut diamonds. These have more facets and will, therefore, reflect light more than the step cuts.

When shopping for the ideal brilliant diamond, you need to pay close attention to the stones cut and polish. For the most brilliance, both of these need to be excellent and precise.

When light hits the stone, it can either be reflected or refracted. Reflection is the bouncing back of the light and this can happen when it hits any of the diamond’s facets. Also, the light will enter the stone and change direction after hitting one of the facets, bouncing off another facet and changing direction as it does so.

A diamond’s rough has some amazing features. These features are what makes the diamond sparkle and shine after proper cut and polish. Since the diamond has a highly dense structure, light slows down after hitting it. There are also numerous electrons in its structure. All this results in spectacular light action.

The critical angle

To have a better understanding of the diamond’s brilliance, let’s take a look at the critical angle. This is the maximum angle by which light can bend and leave a material. In a diamond, this critical angle is 24.5 degrees. Compared to other materials, this is very small.

The advantage of such a small critical angle is that it is much harder for light to escape the stone and will, therefore, be refracted many times inside the stone before leaving through the table and crown. Some of the light that will not leave the diamond through the top will dissipate inside the stone.

But if this is the case, you may wonder why some diamonds have more brilliance than others? It comes down to the diamond cut. Light will escape from the stone through the pavilion if the stone is cut too deep or too shallow. How a diamond is cut also determines what angle the light bends once it enters the stone.

This simply means that the diamond’s pavilion and girdle should be well proportioned. Every part of the anatomy of the stone needs to be cut with the right proportions. Otherwise, the light will not be reflected inside the stone well enough. The diamond needs to be perfectly symmetrical and the facets must be properly aligned.

Once all these factors are met, the diamond will have tremendous brilliance and will draw attention from a long way off. After all, it is this light action from the stone that draws the eye to diamonds.

Diamond Fire 

If you are new to diamonds, the word fire might give off an idea of something mystical and unreal. However, fire in a diamond is a very real thing. It is an important factor to consider when buying a diamond.

One of the main characteristics that you can use to judge the quality of the cut and the clarity of the diamond is its fire. But be careful to observe and evaluate the stone under natural light for the best and most realistic results.

Fire is also referred to as dispersion. Diamond fire is the sparkle that is formed when the white light entering the stone is dispersed into its various colors. Unlike brilliance which is the colorless light from a diamond, fire is the colored light.

When light enters the diamond, it is broken down into its various hues.

Similar to the brilliance of a diamond however, the fire will also depend on the stones cut. When it is cut with ideal proportions, the light will bend and refract inside the stone to maximize the brilliance and the fire.

That said if the stone has less than ideal proportions it will be dull and lifeless without much fire and brilliance.

The stone should neither be too shallow or too deep as this will cause the light entering through the crown to escape through the pavilion instead of being refracted inside the diamond and sent back through the top of the stone.

Diamond fire and cut

This is one more reason to pay special attention to the cut grade of a diamond. The GIA has a scale that ranges between Excellent to Poor cut. The best cut diamonds with the most fire and brilliance will have an excellent, very good or good cut grade.

You can tell how well-cut stone is by its fire. The GIA cut grading system has fire as one of the main factors to use when you want to judge the quality of the diamond cut.

Diamond fire and lighting 

The amount of fire is also determined by the type of light that the diamond is exposed to. You can get the most fire by combining different light sources. The best way to judge the diamond before making that all-important buying decision is to observe and compare diamonds under natural light.

Many jewelry stores will place the diamond under spaced lighting conditions that will make the diamond appear even fiercer.

When you are buying your diamond online, make sure that you have access to 360-degree videos of the stone you are interested in. Also, it’s a good idea to read through the returns policy just in case you do not like the stone when it gets to you.

Avoid viewing the diamond under colored light as this may cause out to paper fierier than it would when under natural light.

Diamond fire and clarity

Clarity has a significant impact on a diamond’s fire. Of course, the stone will not allow much light if it is not clear and the less light that gets into the diamond, the less light that that will be dispersed which ultimately means less fire.

The inclusions inside the stone will get in the way of light that has been refracted. You can judge the quality of stone not just by physically looking for inclusions and imperfections but by the fire. Stones that are a bit low on the clarity scale and have inclusions will have less fire while more clear stones will have more fire.

Diamond fire and cleanliness

Many people fail to understand that for the stone to give off as much fire as possible it needs to be clean. Dust particles will prevent light from getting inside the diamond and any light that will get in will be blocked on its way out.

Without its brilliance, it becomes easier to see the inclusions inside the diamond. Make sure to clean your diamond often with a dry cloth to polish off any dust particles and to maximize its fire and brilliance.

Make sure also to use a stopper on the sink if this is where you choose to wash your diamond. The last thing you want is to lose it in the sink. While you can use a mild soap for cleaning the stone, it is much better to use a cleaning solution that is specifically designed for diamond cleaning. You can get this at jewelry stores.

Makes sure that the soap you use is not too strong. Having dipped the stone in the cleaning solution removes it, and wipe off any dirt.

While diamonds can have a tint of color, generally the clearer the stone the more fire it will have. This is because light dispersion is maximized in whiter diamonds more than in colored diamonds. Of course, colored diamonds can be stunning, but they smoky will not have as much fire as white diamonds.

When you combine the effects of both the diamonds’ brilliance and its fire, you get scintillation.

Diamond Scintillation

This is the sparkle of the diamond. The flashes that you see when the diamond moves around in the light is the scintillation. This means that the sparkle is a dynamic characteristic and the diamond needs to move for its sparkle to be appreciated.

While nature will provide a rough stone, it is up to cutters to make sure that it is ideally cut and polished. Only then will it produce the sparkle. It is a combined result of ideal proportions, symmetry facet alignment, and polish.

Having achieved all this, the light will enter the diamond and come out through the table of the stone.

Consider looking at the brilliant-cut diamond from the crown. One large central facet is called the table and this will be surrounded by many other triangular or star faces. When you look at a diamond’s drawing, it is simple to comprehend.

However, when you look at an actual stone, you will notice that it has many tiny facets inside the facets. These flash as you move the diamond. They are virtual facets and are reflections created from the main facets of the stone.

So simply put, when the diamond has more facets, it will have more virtual facets and vice versa. Keep in mind however that having more facets doesn’t always cause the diamond to have more scintillation. Larger flashes are more ideal than many smaller flashes. It’s therefore about finding the right balance between the number of facets and scintillation.

Fire vs flash scintillations

Two separate factors determine and affect a diamonds scintillation—the fire scintillation and the flash scintillation. You can see the flash scintillation when white light sparkles. On the other hand, fire scintillation is when colored light sparkles.

The white flashes or sparkles, however, are more visible than fire scintillation since white light can be seen in more light conditions.

Scintillation and facet size

Facet size is another factor that will affect the scintillation. A diamond will larger flashes will show its scintillation throughout the crown of the stone.

Since the sparkle of a diamond is also affected by the number and size of the virtual facets. The technology for being able to evaluate and judge the diamonds sparkle continues to develop and evolve. That said, what is at our disposal are what we will use.

Note however that scintillation performance is not the same thing as light performance. An ASET image is used when evaluating scintillation. This is a still image of the stone when it is set under broad diffuse lighting. However, the diamond needs to move to be able to show its scintillation, and therefore the ASET image may not show everything about the scintillation.

With the AGS scintillation analysis and report, diamonds that have the most sparkle will receive the highest score. This is when the sparkle can be seen throughout the top of the diamond’s crown. You can tell whether a stone is well cut by its sparkle. If it shows scintillation on some areas of the crown and not in others then the cut is not ideal.

By AGS scintillation metrics, a grade of 0-0 represents diamonds that have the highest score of flash scintillation and fire scintillation. These swill show flashes of both white light and colored light throughout the crown.

Scintillation maps are used to help compress the motion of a diamond into a single image that can be used in a report. Images of the stone are captured at different orientations and these are used as data in the report.

These images can determine factors such as facet size, dispersions as well as the flash potential of the stone.

The flash scintillation map is used to show the white flashes on the diamond. There are white areas on the map that displays where the flashes are likely to be seen. There are also some dark areas on the map that represents where the white flashes are least likely going to be seen.

The fire scintillation map shows the colored sparks on the stone. It has areas that are lighter than others. These light areas represent where fire flashes are more likely to be seen. Fire flashes will be least likely seen in the dark areas.

The scintillation pattern of the map will show the size of the diamonds sparkle as well as the pattern of the facets. It represents both flash and fire sparkles. It also has some areas that are lighter than others. The light areas are where the largest sparkles will be seen while the darker areas are where the smaller sparkles will be seen.

The diamond scintillation is one more reason why the cut is considered to be the most important of the 4Cs when evaluation your diamond. The cut will directly influence the movement of light in the stone.


How the light is reflected and refracted will influence the diamond’s scintillation.

For maximum reflection and refraction, the facets of the diamond must be perfectly symmetrical. A poorly cut diamond will have poor light refraction and poor light action.

The number of facets matters. Larger fewer facets will have larger flashes while smaller facets will have many tiny flashes. The ideal size diamond will have an ideal size and number of facets.

The diamonds fire, brilliance and scintillation are what gives the diamond its life. Only the most ideal cut diamond will be able to display these factors most efficiently.

Since they are the first to catch your eye, you can easily use fire, brilliance, and scintillation as a way of judging the quality of the cut. Simply put, only the best cut diamonds will have the most fire, brilliance, and scintillation.

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