A Complete Guide to Round Brilliant Cut Diamonds

The round brilliant cut is the most popular diamond shape in the world and accounts for around three-quarters (75%) of diamond jewellery sold worldwide. Belgian engineer Marcel Tolkowsky perfected its proportions in the early 20th century to capture as much light as possible. In this guide, we'll explain how the cut works, what to look for and how to choose a piece you'll treasure for a lifetime.

Round diamond design

Tolkowsky refined the round brilliant cut's proportions with one goal: maximum sparkle. An excellent cut uses precise angles that bounce light back through the top of the stone, giving you the brilliance, fire and scintillation the cut is known for. This is the main reason round diamonds are so versatile. They suit rings, pendants and earrings alike.

How many facets does a round brilliant cut diamond have? 

A round brilliant cut has 57 or 58 facets. The crown holds 33: the table at the centre, 8 star facets, 8 kite facets and 16 upper girdle facets. The pavilion holds the remaining 24: 16 lower girdle facets and 8 pavilion mains. The 58th facet is the culet, a small flat face at the bottom point. Whether a stone has one changes the facet count and the overall look of the diamond. On larger diamonds, a culet can appear as a small dark or grey spot when viewed face up. Most modern stones are cut to a point, with 57 facets.

Round Brilliant Cut Diamonds Work Well with Various Styles

Round brilliant cuts are one of the most versatile diamond shapes, which makes them well-suited to many styles, particularly engagement rings and other diamond rings.

When choosing a design for your round brilliant cut jewellery, consider your partner's style and taste. Do they like the classic, timeless look of a solitaire? Or do they prefer something more modern and sparkly, such as a halo setting?

What to check before you before you buy

Before buying a round brilliant cut diamond ring, check a few things:

• Girdle: Avoid an extremely thin girdle, as the edge can chip during daily wear. A cut graded good to excellent should prevent this, but for peace of mind you can inspect it with a jeweller's loupe.

• Brilliance: Rotate the diamond in white light and look for a bright, even return of light.

• Fire: Under a spotlight, tilt the stone and watch for flashes of orange, yellow, blue and red.

Find your round brilliant cut with Shining Diamonds

We offer round brilliant cut diamonds in both natural and lab-grown, so you can choose the option that suits your budget best. Our diamond experts will help you find the right stone and setting for your proposal or gift. Book an appointment in one of our showrooms across the country today.