How to Buy an Oval Lab Grown Diamond (and Dodge the Bow-Tie)

Almost every oval lab grown diamond has a faint shadow running across its center, shaped like a little bow tie. Most people never hear the term until the stone is already on their finger, catching the light wrong in a restaurant. The good news: the oval lab grown diamond bow tie is predictable, easy to inspect for, and completely avoidable if you know what to look at before you buy. This guide walks you through what the bow tie actually is, why it happens, and the exact specs and habits that separate a lively oval from a dull one.

What the bow tie actually is

The bow tie is a dark, horizontal band across the widest part of an oval (and in marquise and pear shapes too). It is not an inclusion, a flaw, or a grading defect. It is a light-leakage pattern caused by the elongated shape and the angles of the facets in the belly of the stone. When you tilt the diamond, the bow tie shifts and can darken or disappear depending on the lighting.

Here is the part nobody tells you: a slight bow tie is normal and shows up in essentially every fancy elongated cut. The line between an acceptable stone and a disappointing one is whether that dark zone is faint and dynamic, or heavy and static. A heavy bow tie reads as a black gap in the middle of the diamond in almost any light, and once you see it, you cannot unsee it.

Why ovals get a bow tie and rounds do not

A round brilliant is symmetrical in every direction, so light bounces back evenly. An oval is stretched, which means the facets in the center have to do more work to return light at the same angles. When a cutter pushes proportions too far, prioritizing carat weight over light performance, the center facets misdirect light and you get that shadow. So the bow tie is really a cut-quality story, and cut is the one thing that determines whether a diamond looks alive.

This matters even more for lab grown. Lab grown diamonds are real diamonds, chemically, physically, and optically identical to mined ones, which means they follow the exact same optics. A lab oval cut to lazy proportions will throw a bow tie just like a mined one. Growing the crystal in a lab does nothing to fix poor cutting. If you want the full background on the material itself, see our lab grown diamonds explainer.

The proportions that cause a bad bow tie

You do not need to be a gemologist to read the numbers on an IGI report. A few ranges do most of the work. Treat these as starting filters, not hard rules, because the only true test is your eyes on the actual stone.

• Depth: Roughly 58 to 64 percent. Too deep and light gets trapped; too shallow and it leaks straight through the bottom, which can deepen the bow tie.
• Table: Roughly 53 to 63 percent. A very large table can flatten the center and exaggerate the shadow.
• Length-to-width ratio: Around 1.30 to 1.50 for a classic oval. Closer to 1.30 looks fuller and rounder; closer to 1.50 looks longer and more dramatic. Extreme ratios outside this band often come with heavier bow ties.
• Symmetry and polish: Aim for Excellent or Very Good. Sloppy symmetry shows up as an uneven, lopsided bow tie.

One important caveat: IGI does not assign an overall cut grade to fancy shapes the way it does for rounds. That blank "cut grade" field is normal for an oval. It also means you cannot outsource the decision to a single letter. You have to look.

How to actually inspect for the bow tie

The single most useful step costs nothing: look at a real video of the actual stone, not a stock photo. Reputable sellers show 360-degree video of every diamond. Watch what the center does as the stone rotates.

• Look at the center under motion. A good oval's center stays bright and the shadow flickers as it turns. A bad one holds a fixed black band no matter the angle.
• Check for an empty, glassy middle. If the belly looks watery or see-through rather than sparkly, light is leaking through it.
• Compare two or three stones side by side. The difference between a faint bow tie and a severe one is obvious the moment you put them next to each other.
• Ignore the lighting in the photo. Diamond photos are often shot under bright, flattering light. Video under normal rotation tells the truth.

If you want to browse and compare real stones with their certs and videos, our diamond search lets you filter ovals by the exact proportions above, and the oval lab grown diamonds page is a good place to start.

How much does an oval lab grown diamond cost

Lab grown typically runs around 40 to 70 percent less than a comparable mined diamond of the same size and quality. That gap is the real reason ovals have surged in popularity: the elongated shape already looks larger than a round of the same carat weight because more of the surface faces up, and lab pricing stretches your budget further on top of that. Two wins in one shape.

Because we sell direct with no middleman, the savings reach you instead of getting eaten by markup. A bigger budget headroom also means you can prioritize cut quality, the thing that kills the bow tie, instead of overspending to chase carat weight.

One honest note worth saying out loud: lab grown diamonds generally have lower resale value than mined diamonds. If you are buying as a financial asset, that is a real tradeoff. If you are buying a ring to wear and love, which is what most people are doing, it rarely matters, and the price-to-size value is hard to beat.

The 4Cs still matter, but cut leads

For an oval, prioritize in this order: cut and proportions first (this is your bow tie defense), then color, then clarity, then carat. Most people are happy in the near-colorless range, and many eye-clean clarity grades hide their inclusions well in an oval because the brilliant faceting masks them. Spend where your eye can see it. Our 4Cs guide breaks down how the four interact so you can make smart tradeoffs instead of paying for a grade nobody will ever notice.

Setting choices that hide or help the bow tie

The setting will not fix a severe bow tie, but the right one frames a good oval beautifully. A four-prong or compass-set solitaire keeps the stone open and lets light in. A hidden halo or a thin pave band adds sparkle around the center without competing with it. East-west settings, where the oval lies horizontally, are having a moment and can downplay a faint center shadow because the eye reads the stone differently. Browse mountings on our setting browser or start from finished styles in the engagement rings collection.

What to expect when you buy

Every center diamond ships with an IGI certificate, so you have independent documentation of the exact proportions you inspected. Made-to-order rings ship in about 15 business days via complimentary UPS 2-day shipping; in-stock pieces go out in 1 to 4 days. If something is not right, unworn items can be returned within 30 days with a prepaid US label, though fully custom designs are final sale. Our lifetime warranty covers manufacturing defects, not normal wear or loss, and resizing is a paid service priced per ring. If splitting the cost helps, financing is available through Klarna, Affirm, and Afterpay.

The short version

Every oval has some bow tie. Your job is to pick one where it is faint and lively instead of dark and dead, and you do that by reading the proportions on the cert and, more importantly, watching the actual video of the stone in motion. Cut quality is the whole game. Get that right and an oval lab grown diamond gives you a larger-looking, brilliant, conflict-free stone for typically a fraction of mined pricing.

Ready to compare real stones with full certs and 360-degree video? Start with our oval lab grown engagement rings, or filter by your exact proportions in the diamond search. Take your time, trust your eyes, and pick the oval that stays bright when it turns.