Carat is a measure of weight, not size. Two diamonds of exactly one carat can look noticeably different on the finger depending on how that weight is distributed. This is the single most useful thing to understand before choosing a shape.
The short answer
An oval looks larger than a round of the same carat weight. A 1.50 carat round measures roughly 7.4 mm across. A 1.50 carat oval measures roughly 8.5 by 6.0 mm. The oval is longer, and because it runs along the finger rather than across it, the eye reads it as the bigger stone.
Why ovals also cost less
Round brilliants lose more rough crystal in cutting than almost any other shape, and that loss is priced in. At the same weight, color and clarity, an oval is typically 15 to 25 percent less than a round. You pay less for a stone that looks larger, which is why ovals have become the most requested shape we set.
What you give up
Round brilliants are the most forgiving shape there is. Their faceting returns light more completely than any elongated cut, and they sparkle in almost any lighting.
Ovals have two traits worth knowing. The first is the bow tie, a dark band across the center of the stone caused by light obstruction. Every oval has one; in a well-cut stone it is faint, in a poorly cut one it is obvious, and no setting will hide it. The second is that elongated shapes show any warmth in the tips before a round does, which is one reason we work in the colorless range, D to F, as standard.
How each wears
An oval elongates the finger and pairs beautifully with a plain or pavé band. It sits slightly higher, so if she works with her hands, a lower profile or a bezel setting is worth considering. A round is the most robust everyday shape, sits comfortably under gloves, and matches every band ever made.
What we would tell a friend
If the largest visible stone for the money is the priority, choose the oval and put the difference into carat weight. If she is hard on her hands, or wants something that will never look dated, choose the round. Both are excellent choices; neither is a mistake.
We check every oval for its bow tie before we send it. Browse our oval lab-grown diamonds, or ask us to select three for you.
