Inclusions & Blemishes

Diamond Inclusions: Feather | Rare Carat

Diamond feather shown on GIA certificate

Feather as represented on GIA report

Hello diamond enthusiasts! Welcome to the next installment of our ‘diamond inclusions’ series! Before we launch into learning (AND LAUGHING) about feathers, we hope you’ll pop back and have a quick old look at our introduction post about all things ‘diamond inclusions’. It will help you to understand more about why inclusions matter, how they are described on a diamond grading report, and other fun things like that.


What is a Diamond Feather?

It’s important to know about feathers, because they are one of the most common inclusions found in diamonds. A feather actually referred to an internal crack or break in a diamond. These cracks/fractures/breaks can be no problem at all… or big trouble indeed, depending on their size and location and color.

With the more innocuous feathers, they will usually be whitish/transparent in color and you most likely will never see them without a 10x magnifying loupe (and who carries one of those around). They will also not cause any real impact to the integrity and durability of the stone, meaning they won’t cause it to deteriorate over time (cracks/fractures/breaks getting bigger for example).

A round diamond against a gray background has a red circle around a small white line, called a feather

These ‘good’ feathers will be completely enclosed within the diamond itself. Those feathers we can get on board with, and so should you.

What we might call ‘bad’ feathers on the other hand, can be a problem. For instance, they might reach from inside the stone all the way to the surface. This in turn can negatively impact the durability of the stone, because these tiny fractures and cracks can easily grow and expand, eventually even leading to a large crack in the diamond.

A round diamond against a gray background has a red circle around a large break in the diamond, called a feather

If you spot a feather that goes from deep inside the stone all the way to the surface (especially if it’s at the most vulnerable spots such as girdle/culet/facet)… avoid, avoid, avoid. You might also want to avoid feathers that are darker in color, as they can impact the optics of the diamond, especially if it’s somewhere near the top of the diamond.

So there you have it folks, feathers (like the witches in The Wizard of Oz) can be ‘good’ or ‘bad’. Lean more towards the goodies.

If you still need help deciding which ring is right for you, take our 30-second quiz!

Feather Diamond Inclusion FAQs

Are all feathers a big problem, or can some be harmless?

Many feathers are very small and completely internal, so you won’t see them without magnification—and they don’t have any meaningful effect on the diamond’s look or strength. As long as the feather doesn’t reach the surface or sit near a vulnerable edge, the diamond can still be a good buy.

When should I avoid buying a diamond with a feather inclusion?

If the feather runs from inside to the surface—especially along the girdle, the culet, or right on a facet edge—that’s usually a sign to slow down and take a closer look. Such surface-reaching fractures make the stone more vulnerable to chipping or cracking. Also, if the feather is large, dark, or centrally placed so it's visible face-up, it can harm brilliance and viewability.

How can I tell if a feather is noticeable in my diamond?

High-resolution photos and video will usually show whether the feather stands out when you look at the stone face-up. Always check from multiple angles, and make sure the feather isn’t reaching the surface or sitting in one of the more fragile areas of the diamond.
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Dr. Rian Mulcahy
Dr. Rian Mulcahy
Rian is officially a Diamond PhD - just ping us if you’d like to read her fascinating 200-page thesis, titled Facets of Value: An Investigation into the Formation of Worth in the Diamond Market. She has consulted various firms all along the pipeline, from the rough diamond market to the recycled diamond industry. She holds an MA in Globalisation and Development from University College Cork and a PhD in the Sociology of Diamond Valuation from the London School of Economics.