The Bowtie Effect in Oval Diamonds (and How to Avoid It)

In this guide

    By Clint Casmiro, Co-Founder, Smiro Studio, Toronto · Updated September 27, 2026

    Short answer: The bowtie effect is a dark, bowtie shaped shadow across the middle of an oval, pear, marquise or moval diamond. It happens when the centre facets do not return light to your eye. Almost every oval has some. We source and cut bowtie-free ovals so the stone stays bright end to end, and we check every stone on video before you buy.

    Once you see a bowtie you cannot unsee it. Here is how to avoid one.

    What causes a bowtie?

    Elongated brilliant shapes have a shallow zone across the middle. When the pavilion angles there let light leak out the bottom instead of bouncing back up, you get a dark band. It is a cutting issue, not a clarity or colour issue.

    Which shapes get a bowtie?

    Ovals most often, then pears, marquises and movals. Rounds, cushions, emeralds and radiants do not get a classic bowtie.

    How do I spot one?

    On video, not in a photo. A still picture can hide it or exaggerate it. Rock the stone slowly: a mild bowtie that flickers is normal, a dark band that stays put is the one to avoid.

    What is a bowtie-free oval?

    An oval cut with a faceting pattern that keeps the centre lit. It is one of our three signature cuts. Side by side with a regular oval, the difference is obvious.

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    Questions we get about this

    Is a bowtie bad in an oval diamond?

    A faint one is normal. A strong dark band that stays visible as the stone moves is worth avoiding.

    Do all oval diamonds have a bowtie?

    Most have some. Bowtie-free ovals are cut specifically to avoid it.

    Does a bowtie show on the certificate?

    No. Grading reports do not note it, which is why video matters.

    Can lab grown ovals have a bowtie?

    Yes. It comes from the cut, so lab and natural ovals can both show it.

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