Shape is the first decision people make when choosing a centre stone, and the one they regret most often. The two most popular "opposite" choices are round brilliant and emerald cut. They look like nothing alike and suit very different hands and personalities.

Round brilliant

The round brilliant is the 57- or 58-facet shape most people picture when they hear "diamond". It is mathematically tuned to maximise brilliance — light entering from the top reflects around and exits back out the crown. Because of this, it hides inclusions and colour well. It is the safest choice, the most popular, and the most expensive per carat because roughly half the rough stone is cut away.

Emerald cut

The emerald cut is a rectangle with stepped facets and clipped corners. Instead of sparkle, it shows long parallel flashes of light and a hall-of-mirrors effect. It looks modern, architectural and slightly vintage. Because its large open table shows inclusions clearly, emerald cuts need a higher clarity grade to look clean — usually VS2 or better.

Side by side

Round brilliantEmerald cut
SparkleMaximumLinear flashes
InclusionsHidden wellVery visible
ColourHidden wellVisible
Face-up sizeSmaller per caratLarger per carat
LookClassic, bridalModern, art-deco

Which suits your hand?

Round brilliants suit almost everyone. Emerald cuts look particularly elegant on longer, slimmer fingers because their horizontal lines broaden the eye. If your partner wears modern, minimal jewellery, an emerald cut often feels more "them". If they wear classic, sparkly pieces, round is the safer call.