Tips and Tricks

The Guide to Diamond Inclusions | Rare Carat

Think of an inclusion like a birthmark - lots of people have them, sometimes they are obvious, and sometimes even though they are there, you can’t see them (under normal circumstances). This is what we call an eye-clean person. Okay, maybe eye-clean is just used in the diamond biz, but you get the point.

Kinds of inclusions:

What even is an inclusion? Well, hundreds of thousands of years ago when a chunk of carbon was being compressed, a lot of things went right obviously because it has gone from a chunk of organic material to a beautiful, stunning diamond. So good for it. But, sometimes (most times) there were a few things that went wrong too. And that's okay. That is actually one way that you can tell a real diamond apart from other imposter stones - the inclusions. There are some inclusions that only nature could create and thus a tell-tale sign of the real deal.

While inclusions are internal imperfections, blemishes on the other hand are the outer flaws in the diamond.

We’ll start with the most obvious and work our way through.

Carbon flaws

There is a common inclusion you’ll see often in diamonds and that is carbon spots. These will show up as tiny specs to obvious spots of black. Almost like little pepper flakes internally. These specs are actually just carbon bits that didn’t turn into diamond and got stuck in the stone. In a well-faceted stone, you may have to move it around a bit and look at it for a while before they pop out at you. That's because the cutter chooses the right cut style to try and hide those spots. Other times though, in a low clarity graded stone (we’ll get into how these are graded in a bit) all you can see are the imperfections.


A cloud is a grouping of tiny pin-point sized spots inside the diamond. While you can’t usually really see them individually without magnification, sometimes if there is a large cluster of them it can make the diamond look hazy in that spot. Clouds are usually not the worst inclusions to have, but if they are in more inconspicuous areas the better.


A crystal can be made of many things - there have been diamonds found with garnet, sapphire or even other tiny diamond crystals trapped inside during formation. These can be quite obvious, sometimes white, other times blue, red, green or less noticeable and transparent.


A feather is a very nice word for crack or fracture internally in the diamond. While this can be not only an obvious looking imperfection, if the feather is big enough it can create issues when it comes to integrity for the diamond. A hairline fracture can become troublesome and possibly leading the diamond to crack.


Twinning wisp

These can show up in a few different ways - they can be a series of pinpoints, clouds, feathers or clouds, really this means that these inclusions are found on two adjoining planes (mirroring each other), showing up like zebra stripes internally in the diamond.

While there are A LOT of different kinds of inclusions, there are some that are easier to spot than others. Some can really only be seen from under magnification, and others are quite obvious to the naked eye. That's what you definitely don’t want, is a brilliant, gorgeous diamond with a big spot in the middle of it that takes away from all its awesomeness.

While that sounds terrible, there are a lot of diamonds that it's not so bad for inclusions to be present. One of the diamond cutter’s jobs is to choose the right cut style for that diamond in front of them. By looking at where the inclusions are, they can place facets and create reflections in the stone to make it harder to actually see the spots. There are a few exceptions to this though that they can’t help in. If there are imperfections present directly under the table (the flat part on top of the diamond) this gives you a straight show view into that stone, so it will be very obvious if there are inclusions. So how do you tell what's a good diamond and what's not? Well, I thought you'd never ask!

The GIA (Gemological Institute of America) has grading standards for color, cut and clarity in diamonds. The clarity grading will help you to know what grade to look for that fits your budget and know exactly what you are getting in a diamond. The grades are based on how many inclusions there are, how big (noticeable) they are, and where they are located. Here are their grading categories and how to interpret them.

Flawless (FL): No inclusions or blemishes visible to a skilled grader, (or you!)


Internally Flawless (IF): No inclusions, only blemishes are visible


Very, Very Slightly Included (VVS1, VVS2): Inclusions are present, but hard to see or notice


Very Slightly Included (VS1, VS2): Inclusions are minor, and range from difficult to easy to be seen, but are not very obvious


Slightly Included (SI1, SI2): Inclusions are noticeable

SI2.jpg While these are all SI diamonds, you can see the last example, the inclusions are less obvious, placement is key.

Included (I1, I2 and I3): Inclusions are very obvious and can affect the fire and brilliance in the diamond negatively (insert included diamond photo examples)

Okay, so now we know how those grades are set and what they mean. We talked earlier about how different cuts can hide inclusions better than others. If you look at an SI emerald vs a SI round brilliant, you may see that inclusions are very obvious in the emerald vs the RB. This is due to the facets reflecting off each other and masking the inclusion. An emerald has long, chiseled facets and a wide-open table that creates a very open line of sight, this makes it easy to see these unwanted spots. While the reflections can usually help hide these inclusions, sometimes they can do the opposite. Here’s an example of one inclusion reflected all over internally in the diamond:

Carbon spots.jpg

It is usually best (if you can afford it) to go for a diamond that is VS2 or better, but we’ll leave that up to your judgment. You can definitely find diamonds in a lower grade that have less visible inclusions than others. Carbon spots and feathers are going to be the most obvious inclusions, and watch out for how deep the feathers are. Now go find your perfect dream diamond!

Lex Alcala
Lex Alcala
Lex has been studying and diving into the gem world for years. She’s finally able to combine her love of writing and passion for all things gem and diamond related as a writer for Rare Carat. When she’s not working on on creating fun and fascinating articles or studying for her Graduate Gemologist Diploma, she’s hanging with her husband and 3 amazing bonus kids.