The Bow-Tie Effect Explained: Which Shapes Show It
A dark shadow across the centre of an oval, marquise, pear or elongated cushion isn't always a flaw — how to tell a good bow-tie from a bad one.
Short answer: a faint, soft bow-tie is normal and often adds character; a heavy, near-black bow-tie that kills sparkle in the centre of the stone is a real cut-quality problem worth avoiding.
What causes it
A bow-tie is a dark, bow-tie-shaped shadow across the centre of certain diamond shapes, caused by the way their elongated facet pattern interacts with light — at the stone's centre, some facets face away from the light source and reflect the viewer's own shadow back at them rather than brilliance. It's a structural consequence of elongated faceting, not a flaw unique to badly cut stones — which is exactly why it shows up on well-cut examples too, just more faintly.
Which shapes show it
Bow-tie appears on every elongated brilliant-cut shape: oval, marquise, pear, and to a lesser extent elongated cushion. Round brilliants, and step cuts like emerald cut, don't show a true bow-tie in the same way — step cuts can show comparable dark zones from windowing or extinction instead (see our windowing and extinction guide), which is a related but distinct issue.
Good bow-tie vs bad bow-tie
A good bow-tie is soft-edged, doesn't dominate the stone's centre, and can genuinely add contrast and a sense of depth rather than reading as a defect. A bad bow-tie is heavy, sharply defined, near-black, and visibly interrupts the stone's brilliance across a large portion of its face — this is what buyers usually mean when they ask whether "the bow-tie is bad."
Can you avoid it completely?
Not entirely — some degree of bow-tie is inherent to elongated faceting, so "zero bow-tie" isn't a realistic bar for these shapes. What you can control is severity: a well-proportioned stone with the right length-to-width ratio (see our shape-specific buying guides above) and good overall cut quality will show a faint, acceptable bow-tie rather than a heavy one. This is something to judge by eye — ideally on video or in person — since a certificate's numeric grades don't directly report bow-tie severity.
Related reading
Source: bow-tie mechanism and shape-specific severity per multiple current trade-jeweller buying guides (PriceScope, Diamonds.pro, GOODSTONE).
Diamond Windowing and Extinction Explained
Two different ways a poorly cut diamond fails to sparkle — windowing lets light pass straight through, extinction traps it without returning it.
Crushed Ice vs Faceted Diamonds: What's the Difference?
Crushed ice isn't a flaw — it's a deliberate faceting style with its own distinct sparkle. How to tell whether it's the look you actually want.
Diamond Spread Explained: Why Same-Carat Stones Look Different Sizes
Two diamonds of identical carat weight can look meaningfully different in size face-up — spread is why, and it's something you can actually check for.
Compare real stones before you commit
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