4 Things You Need to Know Before Buying Oval Cut Diamonds

The bow tie effect is a dark shadow that appears across the center of some oval diamonds due to uneven light return. A slight bow tie is normal, but a prominent one can make the diamond look dull and reduce sparkle. Since this doesn’t appear on a GIA certificate, visual inspection is essential.

• Check for a minimal bow tie: A soft, subtle bow tie is normal, but avoid dark, heavy shadows.
• Don’t rely on certificates alone: Bow tie intensity isn’t listed on grading reports.
• View the diamond in person or on video: High-quality videos help reveal light performance.
• Look for even brightness: A well-cut oval should appear lively across the entire stone.

Unlike round diamonds, oval diamonds don’t receive an official GIA cut grade, which means buyers need to evaluate cut quality themselves. Reviewing proportions alongside understanding the 4Cs of diamonds and knowing how to read a diamond certification report can make this much easier.

• Check polish and symmetry: Aim for Excellent or Very Good in both for better light performance.
• Review depth percentage: A common preferred range is 58% to 63% for balanced brilliance.
• Look at table percentage: Many well-cut ovals fall between 53% and 63%.
• Use video, not numbers alone: Proportions help, but seeing the diamond’s sparkle in motion matters just as much.

Oval diamonds tend to show body color more than round diamonds, especially near the pointed ends. That’s why many buyers choose to go one color grade higher than they would in a round diamond to maintain a bright, white appearance.

• Follow the one-grade-up rule: If you’d choose an I color in round, consider G or H in an oval.
• Helps keep the diamond looking whiter: Especially important if you prefer a crisp, colorless look.
• Ideal for white metals: Higher color grades often pair beautifully with platinum or white gold settings.
• Flexibility depends on preference: If you like a warmer look or choose yellow gold, you may be comfortable going lower.

An oval diamond’s length-to-width ratio has a big impact on its overall look, from soft and rounded to sleek and elongated. While personal preference matters, choosing the right ratio also affects finger coverage, face-up appearance, and how flattering the diamond looks on your hand. See our guide on Best Oval Diamond Ratio to understand which proportions offer the most balanced look.

• Understand the ratio range: Most oval diamonds fall between 1.20 and 1.50.
• 1.20 to 1.30: Shorter, rounder ovals with a softer look.
• 1.35 to 1.45: The classic sweet spot, balanced and widely preferred.
• 1.45 and above: More elongated shapes that create a dramatic finger-lengthening effect.

This may be the biggest takeaway of all.

With round diamonds, certificates can tell you a lot.

With ovals, they tell only part of the story.

You need both:

• Strong proportions on paper
• Visual confirmation in real life or video

The most beautiful oval diamonds are chosen with both science and sight.

Bow Tie

• Minimal dark shadow
• Even brightness across center

Cut Performance

• Excellent or Very Good polish
• Excellent or Very Good symmetry
• Balanced depth and table
• Strong sparkle in video

Color

• Consider one grade higher than you’d choose for a round

Ratio

• 1.35 to 1.45 for classic proportions
• Choose based on hand shape and personal style