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What Makes a Diamond Shine?

By Frank

Highly experienced diamond polisher who loves to share his knowledge with you. Continues to stun his colleagues with interesting - or simply bizarre - facts about diamonds and gems.

March 6, 2020

Shine bright like a diamond! We have heard the slogan many times. But what makes a diamond shine? Is it the diamond itself or is it just a matter of reflection? Let us explain the details.

Reflection of light

To start off right: a diamond itself does not shine, it reflects light which gives them their beautiful sparkle. This has three main causes: internal reflection, refraction, and dispersion.

marquise cut diamond without and with bow tie effect

Internal reflection

When it comes to light hitting a diamond, only a small part of the light is reflected. Light enters through the top of the diamond and is cut at an angle from inside the diamond. This happens from top to bottom. Depending on where the light hits, refraction and dispersion occurs. This creates natural light and dark areas. The process of dispersion distributes light, which, therefore ‘makes’ a diamond shine.

Refraction

Transparent materials such as diamonds have a critical angle where light reflects internally on to the surface. Because of this reason, the cut of the diamond is extremely important. A diamond should be cut as close to the ideal cut as possible, as shown below. If the cut is too deep or shallow, the light will get lost. Whereas when cut right, the light will be reflected and distributed.

diamond shine and reflection

Source: Hydeblanc Diamonds

As seen above, there are different types of reflections that are linked to different types of cuts. With an ideal cut, a diamond reflects light on the highest level. This means it has a high degree of brilliance. A shallow cut makes for a good reflection. The grade, however, will be a bit darker. A deep cut will give the diamond a fair to poor reflection, due to the lack of brightness. Finally, the very shallow and very deep cut show little brightness and give (very) poor reflection.

The Royal 201

For many years, the regular brilliant cut with 57 facets was considered as the most sparkling diamond. However, in 2007 Royal Coster Diamonds created the Royal 201; a patented diamond cut with no less than 201 facets! This diamond takes “shine bright like a diamond” to a whole other level. The base of the brilliant-cut diamond consists of the simple cut. The diamond is cut with seventeen facets. There are four cross corners, four bezels, four cross-angles, four pavilions, and the table.

Royal 201 diamond

You might think that the more facets a brilliant has, the more light reflects and the more the diamond sparkles. But it doesn’t work that way. Many people tried to make diamond cuts with hundreds of facets but when you put these next to the 201, you see there is more than the number of facets. You see that 201 is the perfect number. And it has been since 2007.” – Donny, one of the creators of the Royal 201

Structure

The Royal 201 is structured in the following way, to optimize its sparkle:

The top consists of 1 table facet and 64 crown facets, of which 8 stars, 8 corners, 16 halves, and 32 mini halves. The bottom consists of 40 facets in total, of which 8 corners/pavilions, 16 halves, and 16 mini halves. And the girdle consists of a total of 96 micro facets (3 for each mini halves).

Triggered?

Want to learn more about the different cuts or admire the Royal 201 in real life? Book a free guided tour.

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