Oval Cut Lab Diamond Guide: Avoiding the Bow-Tie
The definitive guide to buying an oval cut diamond. Learn ideal ratios, color sensitivity, and how to spot a bad bow-tie.
Our team of certified gemologists and jewelry experts provides in-depth analysis to help you make informed purchasing decisions.
Oval Cut Lab Diamond Guide: Avoiding the "Bow-Tie"
The Oval Cut is currently the most requested diamond shape in the world. From celebrity engagements (Hailey Bieber, Kourtney Kardashian, Blake Lively) to everyday proposals, the oval has dethroned the princess cut and is challenging the round brilliant.
Why? Two reasons:
- Size: An oval cut looks significantly larger than a round diamond of the same carat weight because it is elongated.
- Finger Flattery: The shape elongates the wearer's finger, making the hand look more elegant.
However, buying an oval is difficult. Unlike round diamonds, which have a standardized "Cut Grade" from GIA, fancy shapes like ovals do not. You form your own opinion on what looks good. This guide explains exactly what to look for to avoid a bad stone.
The "Bow-Tie" Effect (And How to Avoid It)
Every oval diamond has a bow-tie. It is a dark, horizontal band across the center of the stone that looks like a man's bow tie.
You cannot eliminate it completely. It is a result of light blockage from your head as you look at the stone. However, you want to avoid a prominent bow-tie.
- Good Bow-Tie: Subtle, light gray shadows that add contrast and depth.
- Bad Bow-Tie: A large, black dead zone in the middle of the diamond that does not sparkle.
How to check: Spin the diamond 360 degrees in a high-resolution video. If the center remains dark regardless of the angle, do not buy it. It is a poorly cut stone.
Ideal Proportions: The Length-to-Width Ratio
The "look" of an oval depends on its Length-to-Width (L/W) ratio. This is purely a matter of preference, but the market has distinct favorites.
| Ratio | Appearance | Popularity | | :--- | :--- | :--- | | 1.30 - 1.35 | Classic Oval | Most popular. Traditional, balanced look. | | 1.36 - 1.45 | Elongated Oval | Trending. Looks larger and more elegant on the finger. | | 1.50+ | Very Elongated | Looks very large but risks losing brilliance at the tips (mushy ends). |
Recommendation: Aim for a ratio between 1.35 and 1.45. This is the "Goldilocks" zone where you get maximum finger coverage without sacrificing light performance.
Color Sensitivity: Ovals Show Warmth
Oval cuts tend to show body color more than round brilliants, especially at the tips (the ends of the oval). This means you need to be slightly stricter on Color Grade.
- For White Gold / Platinum Settings: Stick to G Color or higher. An H color oval might show a faint yellow tint at the tips against white metal.
- For Yellow Gold / Rose Gold Settings: You can safely go down to I Color or J Color. The yellow metal will mask the warmth of the diamond.
Clarity: Hiding Inclusions
The good news is that ovals hide inclusions well. The brilliant facet pattern (similar to a round cut) makes it difficult to spot small flaws.
- VS2 is the sweet spot. It will always be eye-clean.
- SI1 is often acceptable. As long as the inclusion is not a black crystal right in the center (the table), an SI1 oval can look perfect to the naked eye.
Lab Diamond vs. Natural Oval Price
The price gap here is massive.
An excellent cut, 2-carat, G color, VS1 oval natural diamond costs approximately $20,000 - $25,000. The exact same diamond grown in a lab costs approximately $600 - $1,000.
Because ovals are so popular, finding a well-cut natural oval is extremely difficult and expensive. Lab diamonds allow you to be picky about the cut quality without blowing your budget.
Where to Buy
Because ovals do not have a standard cut grade, you must see the diamond in high-definition 360° video before buying. Never buy an oval based on the certificate alone.
- James Allen: Best imaging technology. You can clearly see the bow-tie intensity.
- Clean Origin: Excellent selection of higher-quality lab ovals (VVS/VS).
- Rare Carat: Good for comparing prices, as oval pricing varies wildly.
Final Checklist
- Check the Bow-Tie: Ensure it is not a black hole.
- Verify the Ratio: Ensure it is between 1.35 and 1.45 for the best aesthetic.
- Inspect the Tips: Ensure the color doesn't concentrate (look yellow) at the ends.
- Confirm the Setting: If buying a large oval, ensure the setting has a "gallery rail" or hidden halo to support the prongs, as ovals can snag easily.
About this guide
Written by the TheCaratCut Editorial Team. Our recommendations follow our editorial policy, and we may earn commissions through affiliate links. See our affiliate disclosure.