Natural Oval Diamonds

An oval spreads its weight along the finger, so it reads larger than a round of identical carat — usually by around a tenth. That is the whole appeal, and it is also why an oval has to be judged on two things a certificate barely mentions.

The first is the length-to-width ratio. Between roughly 1.35 and 1.50 an oval looks elongated and elegant; below that it drifts towards a fat round, above it starts to look stretched. There is no correct number, only the one you prefer, but it is worth deciding before you look at stones rather than after.

The second is the bow-tie: the dark band across the waist that every oval has to some degree. A faint one adds contrast and life. A heavy one is a dead zone that no setting will fix. No grading report scores it, which is precisely why we put a 360° video on every stone — thirty seconds of rotation tells you more about a particular oval than the entire report does.

On mined ovals, buying at 1.40ct rather than 1.50ct is the sensible saving. The face-up difference is well under half a millimetre; the price difference is not.