What is the Oval Diamond Bow Tie Effect?

Oval diamonds are a timeless, elegant choice—offering the brilliance of a round diamond in a more elongated, finger-flattering shape. But if you’ve started researching oval diamonds, you may have come across the term “bow tie effect.”

What is it? Is it a flaw? And how can you choose an oval diamond that avoids it?

In this blog, we’ll explain the bow tie effect, what causes it, how to assess it, and what to look for when buying a lab grown oval diamond for your engagement ring or fine jewellery.

What Is the Bow Tie Effect?

The bow tie effect is a visual shadow that appears across the centre of certain elongated diamond shapes—most notably oval, marquise, pear, and radiant cuts.

It appears as two dark triangular areas near the centre of the stone, resembling a bow tie. It is most visible when viewed face-up under light.

A bow tie can range from:

• Barely noticeable (adds depth and contrast)

• Mild or moderate (common in many stones)

• Heavy or harsh (distracting dark band that reduces sparkle)

What Causes the Bow Tie Effect?

The bow tie effect is a result of light obstruction—when light doesn’t reflect back to the eye properly from certain angles within the diamond. This typically happens due to:

• Poor facet alignment in the pavilion (bottom half of the diamond)

• Shallow or deep cutting angles

• Asymmetrical proportions

• Inadequate light return across the centre

It’s a natural consequence of the elongated shape, but not all oval diamonds exhibit it in the same way.

Is the Bow Tie Effect Always Bad?

Not necessarily.

A subtle bow tie can actually enhance visual depth and contrast, making the diamond appear more dimensional. However, a strong or harsh bow tie—where the centre of the diamond looks dull or lifeless—is typically considered a negative.

What matters most is how the bow tie interacts with the diamond’s brilliance. A well-cut oval diamond will have:

• Bright flashes of light across the entire stone

• Balanced sparkle from side to side

• Minimal or elegant shadowing in the centre

💎 View a well-balanced, bright-cut example in the
👉 Luna Oval Solitaire Ring, which offers a soft, elongated profile without harsh bow tie shadows.

How to Spot a Bow Tie Before Buying

Because bow ties are about light performance, they can’t be judged by certification alone (e.g., IGI or GIA reports don’t mention bow tie visibility).

Here’s how to assess it:

1. View the diamond face-up under good lighting

2. Rotate it slightly to see how light moves across the centre

3. Look for symmetry and sparkle through the centre zone

4. Ask for videos or in-person inspection if shopping online

A reputable jeweller—like Diamond Lab—can hand-pick oval diamonds with beautiful light return and minimal bow tie appearance.

Ideal Proportions to Minimise the Bow Tie

While there’s no “bow tie grade,” certain dimensions help reduce the effect.

• Length-to-width ratio: Ideal is 1.35 to 1.50

• Table %: Around 53–63%

• Depth %: Around 58–63%

• Symmetry: Must be excellent to very good

• Polish: Excellent to very good

These proportions promote better light distribution, especially through the centre.

Do Lab Grown Oval Diamonds Show Bow Ties?

Yes—lab grown oval diamonds can show the bow tie effect, just like mined diamonds. The growth method (CVD or HPHT) does not directly impact the bow tie; it is entirely about cut quality and proportions.

At Diamond Lab, we hand-inspect each oval lab diamond and offer only those with excellent light performance, clean symmetry, and minimal bow tie shadows.

Final Thoughts: What to Remember About the Bow Tie

• The bow tie is not a flaw, but it can be a distraction in poorly cut diamonds

• Mild bow ties can add depth; harsh bow ties reduce brilliance

• Always view or request videos to see how the diamond performs under light

• Focus on cut quality, symmetry, and face-up sparkle to get the best result

Want Expert Help Choosing an Oval Diamond?

At Diamond Lab, we specialise in helping you choose oval diamonds with brilliant sparkle, ideal proportions, and no unwanted bow tie shadows. Let’s find the perfect one for your dream setting.

📍 Book your consultation in Perth or online