• The bowtie effect is a term for the dark area seen in diamond shapes like the oval, marquise and pear which takes the shape of a bowie
    • It is caused by a misalignment of facets which then form shadows in the diamond
    • It could be almost invisible, or very visible on visual inspection
    • Diamonds of the affected shapes that do not have bowties are rare
    • Diamond bowties are not stated in grading reports, therefore physical inspection must be made.
    • Where physical inspection is not immediately possible, videos and pictures from different angles and lighting must be seen.
    • The things to consider when buying a diamond with a bowtie include:
      • The size of the bowtie
      • How obvious the bowtie is
      • Other characteristics of the diamond-like:
        • Cut: A poor cut would always perform badly, with or without bowties
        • Color: can mask the bowtie or make it more obvious
        • Clarity: Other inclusions present can be worse than the bowtie
        • Carat: the size can affect how obvious the bowtie is

James Allen loose diamonds

So many people understand the things to look out for ina diamond. You might be a guru when it comes to the 4Cs –cut, clarity, color, and carat. You might even give friends advice on what to look out for when they want to purchase diamonds.

But not many people are aware of another thing to look out for in some diamond cuts – The Bow Tie effect.

When light rays hit a diamond, they are supposed to be reflected or refracted by the facets of the diamond. When the facets are not angled optimally, because of the shape of the cut, then areas of darkness might be seen.

The bow-tie effect is a dark area in the outline of a diamond which is seen in some diamond shapes. It is formed by facets that are not optimally placed. These misaligned facets then cast a shadow, which takes the shape of a bow tie, hence the name.

The bowtie effect is seen in shapes like the pear, the marquise, the oval and sometimes heart-shaped diamonds.

It can also be in varying degrees; some are very visible and would affect the light performance and diminish the quality of the diamond. While others are almost invisible and would not affect the diamond’s quality and value.

For the oval pear and marquise shapes, finding a diamond that is not affected by the bowtie effect is very rare.

This is because even in well-cut diamonds, the bowtie effect would still be present. Bowties are not always due to poor cuts, but they can and would be worsened by poor cuts!

Therefore, the onus lies on the buyer to consider to what extent they can accommodate bowties in their diamond.

When bow ties are mild, they are hardly visible and they might even contribute to the fire and scintillation of the diamond when it is viewed. They can blend so well with the diamond’s facets that the shadow cast fits into the outline of the diamond and so the bow tie is not noticeable. Such bowties would not significantly lower the price of the diamond.

However, when a bowtie casts a huge dark area at the center of the stone, then light performance is reduced. There would be no scintillation or fire throughout the zone and the bowtie would be so conspicuous that the value of the diamond would be significantly reduced.

Diamond bowties are not stated in grading reports.  This is why the emphasis is placed on visual inspection of any diamond before purchase. You must get to physically examine your diamonds before buying them. If physical contact is not possible, make sure your online retailer has high definition videos and pictures that display the diamond from different angles and without any colored backgrounds so that you can properly observe if there are bowties in the diamond.


So, the first thing as we have mentioned is that for any of the shapes affected, you would rarely find one without a bowtie. Experts even have some disagreement on whether a bowtie affects a diamond or not.

Irrespective of whichever side you choose one thing is clear: Not everyone would be comfortable with having a dark area in their diamond. Whether this affects the structure or integrity or even the performance of the diamond is another subject matter entirely. The consumer’s preference is the most important factor and it is the determinant factor.

Therefore, a bowtie should not deter you from buying a diamond you are in love with. However, the following factors should be considered when making a purchase of the diamond:

  1. The size of the bowtie: If the bowties are large enough to take a significant portion of the diamond, then you might want to consider another diamond.
  2. How obvious is the bowtie? Does it dominate the entire appearance of the diamond or does it blend well? One way to know when to completely rule a diamond out is when the bowtie is the first thing that you see when you look at the diamond.
  3. Other characteristics of the diamond-like the cut, clarity, color and the carat. A poorly cut diamond would have a poorer visual appeal, even without the bowtie.
  4. Some colors can help to mask the bowtie even if it is present, while some colors would make it more obvious.
  5. The carat too can contribute; larger diamonds with large bow ties would have a very poor appeal, while a smaller diamond with a larger bowtie might even be worse. A larger diamond and a small bowtie might perform well. All of these should be taken into consideration
  6. The presence of other inclusions should also be considered. If a diamond has an obvious bowtie and then some obvious inclusions, it might not make for a good purchase.
  7. Your preference: What do you want?

In conclusion:

while bow ties might not be graded or even appear in reports in the first place, they are significant enough to cast a dark area in the diamond. Since not everyone is comfortable with that, caution should be taken when purchasing.

Again, there is also nothing wrong with buying a diamond with a bowtie as long as it blends well with the surrounding, it does not affect the appearance significantly and most importantly, it is what you want!


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