Skip to Content

What Is Diamond Brightness? What Makes A Diamond Shine?

What Is Diamond Brightness? What Makes A Diamond Shine?

Diamonds aren’t so sought after because they’re rare or durable – they’re sought after because their brilliance can outshine anything in the room. But what gives them that brilliance?

Several factors impact a diamond’s brightness – from the quality of the cut to how it was formed.

This article will cover everything you need to know about diamond brightness. We’ll start from the basics and move on to more advanced topics, such as the difference between diamond brilliance, fire, and scintillation.

So, let’s start with the basics – what is the brightness of a diamond?

What Is the Brightness of a Diamond?

Undoubtedly, diamonds are the stars of many of the world’s most beautiful pieces of jewelry. But what makes these precious gems shine the way they do?

The short answer – diamonds are expertly cut and polished to maximize their natural brilliance. 

The full answer is much more detailed and complex, meaning we need more time to answer in full.

Diamonds get their brightness from dispersion, reflection, and refraction. So, let’s get more in-depth about these three things.

Reflection is a fancy word for the light that hits the diamond and immediately gets reflected, giving it its signature shine. Although this glimmer is impressive on its own, it’s only the tip of the iceberg of the true radiance a diamond can display.

Only a small portion of the light that hits the diamond gets reflected. Most of the light just passes through it.

As the light beam moves through the diamond, it gets scattered and fractured. This creates a diamond’s signature sparkle. The thing that makes the diamond sparkle is called refraction. Put simply, diamonds are very small, complicated prisms.

The light hits the top of the diamond and then gets angled around the insides before it gets aimed back towards the top and through the surface.

The result is the rainbow effect known as dispersion. This dispersion effect greatly adds to the diamond’s shine.

Refraction and dispersion also create natural light and dark areas in the refracted beam of light. These areas depend on where the light hits along the diamond’s planes.

Although these dark areas might seem counterproductive, they’re the “secret sauce” needed to achieve the diamond’s trademark shine.

The dark is the perfect contrast to the light that gets refracted. It intensifies the light. It’s not too dissimilar to a candle flame – the candle always looks brighter if it’s lit in a dark room.

It all boils down to contrast. If diamonds didn’t have contrast, they just wouldn’t shine that brightly or impressively.

Another thing that greatly impacts a diamond’s brilliance is the cut. 

Difference Between Diamond Brilliance, Fire, and Scintillation

Most people evaluate diamonds based on how much they sparkle. Although choosing a precious stone this way is legitimate, the sparkle is not just a single thing.

Diamond fire, brilliance, and scintillation are the three factors that make this precious stone shine brightly with flashes of bright light,

So what are diamond fire, brilliance, and scintillation? Let’s find out!

  • Diamond fire is also known as dispersion. This is the colored sparkle you can see when a diamond is exposed to light. Dispersion is caused by the light getting broken down into spectral hues when it enters the diamond. Diamonds that have small tables and steep crown angles produce more fire because this combination returns less light. In other words, less light return makes it easier to see the diamond’s colorful flashes that usually get outshined by bright white sparkles.
  • Diamond brilliance is the white light that gets emitted from the precious stone. This is the foundation of this gem’s beauty. There are two components to diamond brilliance, and that’s brightness and contrast. Bright diamonds perfectly return light. A diamond with deep or shallow cuts will be less bright because the light that enters it leaks out. However, to be brilliant, a diamond needs more than just brightness. A bright diamond also needs a fair amount of light contrast. For instance, a sheet of plain white paper will appear less lively when you put it on a chessboard.
  • Diamond scintillation is the flashes of light you get from facet to facet towards the center of the stone when you move it. An ideal diamond should have many flashes that spread across its surface.

What Affects the Brightness of a Diamond?

It’s pretty true that the clarity of a diamond is essential for its appearance. However, it’s not the only factor you should look for when shopping around for this precious gem. 

When you look at the 4Cs of a diamond, the cut should be seen as the most essential. However, you should also look at the diamond’s brightness. After all, there’s no point in having a perfectly cut diamond if it doesn’t have that signature brilliance.

So, let’s go over the factors that affect diamond brightness. We’ll first start with clarity and move on from there.


To be perfectly honest, diamond clarity doesn’t always affect its brilliance. At least not as much as people think. A diamond with a low clarity grade is not always less bright than a diamond with high clarity.

Keep in mind that high-clarity diamonds don’t always look much different in terms of brightness from mid and low-clarity diamonds of similar color and cut.

The clarity of the diamond plays a role in how brightly it shines. Blemishes and knicks on the surface of the diamond limit the amount of light that can enter it. Inclusions also prevent the light from moving freely within the gem.

These imperfections are like speed bumps on the road and affect how the light travels through the diamond. The fewer imperfections, the more brilliant the diamond is since there’s nothing to stop the light from moving freely.

Most diamond inclusions are tiny and not visible enough to affect their brightness directly. Unless you’re looking at a diamond with a visible inclusion, the impurities inside it don’t affect how light travels through it.


A diamond’s color is graded by the Gemological Institute of America, which uses letters from D to Z to grade its color. The more colorless the diamond, the higher its quality. Diamonds with the color grade D are nearly colorless, whereas diamonds on the lower scale have a more intense yellow tinge.

Common misunderstanding jewelers hear from customers is that diamonds on the lower color scale have less sparkle and brilliance. This is not always true.

If you go for a brilliant round diamond with a color grade H or above, the cut is what makes the diamond bright and beautiful. 

Clarity affects diamond brightness more than its color. Even a corduroy Google search will return thousands of diamonds that are all yellow and are just as bright as colorless diamonds.


The cut of the diamond affects its brightness the most. This is because the cut is what dictates how the light travels through the diamond.

If a diamond is cut too deeply or shallowly, much of the light will get lost. This means it doesn’t bounce back as it’s supposed to. If the cut is bad, the refraction will let the light slip out the bottom of the diamond. This is why the diamond shape is so essential to its brightness.

An ideal cut should reflect all the light that enters the diamond back to its top. These days, the most popular diamond designs aim to provide the best light performance possible.

These cuts are made to enhance the diamond’s brilliance by using its natural properties and complex angles. This way, diamond cuts don’t just provide superb gleam but also assure the diamond’s shape is aesthetically pleasing.


While not a part of the 4Cs of the diamond, one of the most critical elements of the diamond having the right amount of brightness is symmetry. Symmetry is also essential to the diamond’s cut.

A diamond must be even on all ends, with all the facets cut. The light won’t refract correctly if the symmetry is off, even by a single degree.

Once the diamond is painstakingly cut and shaped to bounce the light, the final step is to polish it. Polishing has a long-lasting effect on the diamond’s brightness since it eliminates any blemishes and roughness from the diamond’s surface.

What Cut of Diamond Shines the Brightest?

Certain diamond cuts provide more brightness than others. In most cases, diamonds with more facets are the brightest. However, this isn’t always necessarily better. Quite the contrary, the ideal number of facets on a diamond is exactly 58.

Let’s take a look at which cuts produce the most brightness and sparkle.

Related Read: Which Diamond Cut Has the Greatest Number of Facets?

Round Brilliant Cut

The round brilliant cut is undoubtedly the cut that produces the most brightness and brilliance. This faceting pattern has exactly 58 facets and ensures the light can go through it so that it creates perfect sparkle. 

A round-cut diamond has the ideal shape and is currently one of the most popular diamond cuts on the market. This cut is the brainchild of Marcel Tolkowsky and was first done in 1919 as a part of his Ph.D. thesis. 

Round-cut diamonds are more expensive than other cuts since they provide the best sparkle.

Cushion Cut

Although cushion-cut diamonds don’t provide the same brightness and sparkle as round-cut diamonds, their cushion-like shape is highly effective at producing high levels of brightness and sparkle. Another cool thing about the cushion cut is that it produces fantastic fire.

Princess Cut

A princess cut is usually square in shape but can also be rectangular. However, as it’s the case with round-cut diamonds, princess cuts also have 58 facets. This means princess-cut diamonds have excellent brightness and also produce a lot of sparkles.

Emerald Cut

Emerald cut diamonds usually have larger surface areas and are long and rectangular in shape. These diamonds feature step cuts and straight linear facets that run parallel to the center of the stone. The brightness of emerald-cut diamonds is a bit more subtle and provides flashes of light rather than brilliant sparkles.

Radiant Cut

The radiant cut is very similar to round and emerald cuts. However, radiant cut diamonds feature 70 facets. While these diamonds don’t have intense brightness as other diamonds on this list, they offer superb sparkle and brilliance.

Oval Cut

Oval-cut diamonds are very similar to round-cut diamonds. However, they have only 56 facets. What this means is that they’re a bit less bright than round-cut diamonds but are still pretty bright. They’re an excellent alternative to round-cut diamonds.

Pear Cut

Just like round-cut diamonds, pear-cut diamonds feature 58 facets. As their name suggests, these diamonds are shaped like a pear. Unfortunately, pear-cut diamonds aren’t as bright as other cuts, but they make up for it with their unique shape.

Heart Shape

Besides their unique design, these diamonds are pretty bright. Just like round-cut diamonds, heart shape diamonds have 58 facets and are just a bit less bright.


So what is diamond brightness? Let’s do a quick overview at the end.

Diamond brightness is nothing more than just how much light a diamond produces when you look at it. The thing that affects it the most is the cut.

If the cut is too deep or too shallow, the light just won’t pass through the diamond in the right way, and it will simply leak the light.

At the end of the day, diamond brightness is just a small part of the overall appeal of this precious rock. Diamonds with less brightness also have a certain appeal.

They’re more subtle, and their dim fire can be hypnotizing under the right conditions.

Moreover, dimmer diamonds tend to cost much less than brighter ones. So, if you’re on a budget and looking for a nice shiny rock, going for a dim diamond isn’t such a bad idea.