The way the light hits has a lot to do with why diamonds shine so bright

Quick Notes:

  • How does light even work?

  • Creating a diamond takes a lot of heat and a lot of pressure

  • There’s more than one type of light refraction

Diamonds have long been known to be a girl’s best friend. The rare and precious stones have been indicators of class and high-society. There is even some controversy about how they’re mined throughout the world. There’s such thing as a blood diamond, after all.

But why are they so revered? Is it because of their rarity, or perhaps it’s all been a really good spin thanks to a diamond advertising company? The true reason for their popularity may never be fully confirmed, because of how many different reasons there are for people to love them, but one thing is for sure: The way light hits the diamond has a lot to do with why they’re so beautiful.

What exactly is light?

In the simplest terms, light is just your basic electromagnetic radiation. There is a spectrum of different types of light, some of which are viewable by the human eye, and some of which are not. The light that we can see has a wavelength of 400–700 nanometers.


The light on the spectrum that humans can perceive falls between ultraviolet and infrared and that spectrum is what makes up the vast array of colors that paint our world. But what does that have to do with diamonds?

Diamonds are Mother Nature’s wild creations

A diamond is clear and colorless and is formed of pure carbon and crystalized over time. A natural diamond can only be formed about 100 km into the earth after a ton of pressure, and high temperatures form the carbon together.

Frequently, a volcanic eruption will shake these crystals free and send them flying into the air, eventually falling back down to the ground. After that happens, they are left to be dug up and turned into your next favorite necklace or, more likely, an engagement ring.

When light hits a diamond, magic happens

The speed of light slows down when it hits a diamond. When the speed slows, the waves then bend, creating a different picture of color that the eye can see. After the light goes through the diamond, it speeds right back up again, and the different wavelengths disperse among the air.

Due to the diamonds geometric prism-like shape, when the light exits, it creates a rainbow of colors much like the way a rainbow is formed from water vapors in the sky after heavy rainfall.

Depending on the cut and quality of the diamond, those colors may vary. The way light hits the diamond will also affect how it shines greatly. If it’s hit perpendicularly, it slows significantly, and the rainbow effect might not be as prevalent, or even there at all. But at any other angle, refraction occurs, and they give off their own little light show.

Not all light sources are the same.

There are different types of diamonds, all of which will give off a different kind of light. Fire, brilliance, scintillation, and luster are the main four. The lighting also affects what key type will show through. In fluorescent lighting, the diamond is more likely to give off the fire look, while natural daylight will showcase its most true lighting form.

A dimmer light will show off the brilliance of a diamond, while a spotlight will show off more of the fire type lighting it refracts. It all depends on the type of light, and diamond retailers know all the tricks to emulate the right kind of lighting to make a diamond appear the way they want it to.

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