Understanding the Bow Tie Effect in Oval Diamonds

The bow tie effect refers to a darkened shadow that stretches across the central portion of elongated diamond shapes such as ovals, pears, and marquises. When noticeable, it resembles the shape of a classic black bow tie, appearing as two dark triangular areas meeting in the middle.

This effect is not considered a clarity characteristic or a structural flaw. Instead, it’s the natural result of how light interacts with the diamond’s internal facets. The challenge (and the delight) lies in finding an oval where the bow tie heightens the diamond’s depth, rather than diminishing its brilliance.

“Every fancy-shaped diamond has its own optical personality. And for an oval diamond, the bow tie is inevitable,” explains Ken Leung, founder of Ken & Dana Design. “For me a good oval is one where the bowtie in the middle is subtle and gradual as opposed to a hard delineation between brilliance and a dark center.”

The bow tie effect results from light obstruction. Specifically, when certain pavilion facets fail to reflect light back toward the viewer. When a diamond is cut in a way that disrupts this light return, dark patches form where the light drops out.

“When we evaluate ovals in our studio, we never rely on the certificate alone,” Ken & Dana founder Ken Leung shares. “Two stones with identical specs on paper can look completely different in person because the bow tie is all about real-world light performance.”

Several key factors influence this effect:

1. Length-to-Width Ratio

The length-to-width ratio shapes the overall look of an oval diamond—and it also plays a meaningful role in how the bow tie effect appears. The good news is that both shorter and more elongated ovals can display beautiful, balanced bow ties when they’re well cut.

• Shorter ovals in the range of 1.30–1.38 often have a naturally harmonious distribution of light. Their proportions make it easier for the cutter to achieve even brilliance, which can result in a soft, subtle bow tie that adds dimension without dominating the center of the stone.

• More elongated ovals in the range of 1.45 and up bring an elegant, finger-flattering look that many people adore. Their stretched proportions create a graceful, refined presence. With elongated shapes, the path that light travels is slightly extended, which means the bow tie can show a bit more, but with thoughtful cutting, these diamonds deliver breathtaking brilliance and captivating contrast.

The key is evaluating each stone individually. With the right craftsmanship, any ratio can display a bow tie that feels like an intentional part of the diamond’s personality.

2. Pavilion Depth and Angle

The pavilion is the lower half of the diamond, responsible for bouncing light back up to the viewer. If the pavilion is too shallow, light leaks out of the bottom rather than returning to the eye, darkening the center. If it’s too deep, light reflects at angles that don’t reach the viewer head-on, creating the same effect.

Even slight deviations in pavilion angle (sometimes less than a single degree) can drastically influence the bow tie’s visibility.

3. Facet Alignment and Symmetry

An oval’s brilliance depends heavily on consistent facet architecture. If opposing facets are misaligned or uneven, the pattern of light and shadow becomes irregular. While perfect symmetry isn't required, well-balanced precision helps distribute light evenly across the stone, softening any potential bow tie and enhancing the fire.

4. Viewer Angle and Movement

A strong bow tie will stay dark from every angle. A soft, appealing one will come alive with movement, shifting in intensity, dissolving into sparkle, or disappearing entirely as the diamond tilts. Light performance that dynamically responds to movement is a hallmark of exceptional cutting.

Contrary to popular belief, a bow tie is not inherently negative. In fact, many of the most desirable ovals have a delicate, understated bow tie that gives the diamond personality, structure, and visual depth. It creates contrast, which is essential for the diamond to sparkle with dimension rather than appearing flat or overly uniform.

Problems arise when:

• The bow tie dominates the center of the diamond

• The dark areas do not brighten with movement

• The shadow covers too much surface area

• The effect distracts from the rest of the stone’s brilliance

A diamond with a harsh bow tie can appear dull, regardless of its size or clarity. A well-balanced one, however, enhances the stone’s beauty by adding a natural rhythm of light and shadow.

Since laboratory grading reports don’t assess bow tie intensity, the only way to evaluate it is visually. This is where expert guidance and high-quality imaging become indispensable.

1. Examine the Diamond in Multiple Lighting Environments

A strong bow tie remains consistently dark under nearly all lighting conditions. Viewing the stone in varying light environments will reveal whether the shadow is persistent or adaptable. To get a full picture of a stone you’re considering, see it in day-to-day environments: bright diffused lighting, natural outdoor light, and soft indoor lighting.

2. Watch How the Stone Behaves in Motion

A beautifully cut oval should shimmer, brighten, and shift as it moves. The bow tie should blend into this movement, sometimes visible, sometimes dissolving into brilliance. A static, unchanging bow tie—especially one that appears “dead” or inert—is a sign of poor cutting.

3. Assess the Brilliance in the Upper and Lower Halves

The ends of the oval (called the “shoulders”) should exhibit strong, even fire. If these areas sparkle but the center remains opaque or murky, the bow tie may be too intense.

4. Compare Multiple Ovals Side-by-Side

Even three stones with similar specs can look completely different when viewed together. Direct comparison is the fastest way to determine your preferences and calibrate your eye for subtle details.

Because of how elongated shapes distribute light, nearly every oval diamond will exhibit some degree of bow tie. The goal isn’t total elimination; it’s achieving an elegant, balanced interplay of brightness and contrast. When selecting your diamond, these guidelines can help you identify stones with the strongest chance of showing an attractive bow tie:

1. Look for “Even Fire” Across the Stone

An oval with well-distributed brilliance will sparkle from edge to edge. The bow tie may appear subtly, but it won’t disrupt or dominate the center.

2. Rely on 360° Video and High-Resolution Imagery

Because bow tie intensity is not recorded on grading reports, purchasing an oval without visual review is risky. Clear video allows you to see the stone’s personality in real motion, revealing much more than static photos or specifications.

3. Consider the Faceting Style

Different faceting styles can influence the appearance of the bow tie:

• Standard brilliant ovals exhibit strong fire patterns that may create more noticeable contrast.

• Modified brilliant ovals often break up the light differently, which may soften the bow tie’s appearance.

Neither is inherently better, it’s simply a matter of preference and how the individual stone performs.

4. Don’t Overweight the Certificate

A GIA or IGI report tells you about color, clarity, and measurements, but not how well the diamond handles light. Visual inspection always takes priority for oval cuts.

5. Work With Jewelers Who Understand Fancy Shapes

Fancy shapes require a trained eye to evaluate properly. A jeweler who specializes in them can guide you toward stones with beautifully balanced performance and a harmonious bow tie.

Experienced jewelers and designers take a proactive, meticulous approach when selecting oval diamonds to ensure that the bow tie is elegant rather than overpowering. They may:

1. Pre-Screen Large Batches of Stones

Fancy shapes vary widely, even within the same cutting parameters. Reputable jewelers often review dozens of stones to handpick the few that perform exceptionally well.

2. Reject Diamonds With Dead Centers

Any stone displaying a static, unresponsive dark patch is immediately set aside, regardless of size or color grade.

3. Use High-Resolution Imaging and Rotational Video

By evaluating the diamond from all angles (both still and in movement) jewelers can ensure that the bow tie blends gracefully into the stone’s brilliance.

4. Prioritize Symmetry and Facet Balance Over Simple Size

Larger diamonds are tempting, but if the bow tie intensifies with scale, they may offer less visual appeal. Many experts favor slightly smaller diamonds with superior light behavior.

5. Favor Stones From Experienced, Fancy-Shape-Focused Cutters

Not all diamond cutters handle elongated shapes well. Jewelers often build relationships with cutting houses known for producing consistently beautiful ovals.

“Our clients often fall in love with ovals, but they can be a tricky shape to get right because of the bow tie effect,” explains Ken Leung. “That’s why we handpick each stone, because a certificate can’t tell you if it has that beautiful, glowing center that makes an oval truly memorable.”

A bow tie is not a flaw, it’s part of the oval diamond’s identity. The beauty lies in selecting a stone where the bow tie adds subtle contrast and depth without overshadowing brilliance. With the right guidance, you can enjoy all the sophistication of an oval diamond, complete with a gracefully balanced bow tie that enhances its natural charm.