Diamond Inclusions & Clarity: What They Are and What Matters (2026)
Last Updated: October 20, 2026
Quick Answer
What are diamond inclusions? They are the tiny natural features sealed inside a diamond as it forms, like a feather, a crystal or a faint cloud. Almost every diamond has them, and clarity grading is simply a measure of how many there are and how easy they are to spot. The grade that matters for most buyers is eye-clean: a diamond with no inclusions visible to the naked eye. That usually means VS2 or SI1, well below the flawless grades, and it is where your money goes furthest. Lab-grown diamonds have inclusions too, just slightly different ones.
Table of Contents
Clarity is one of the 4Cs, and it is the one most often misunderstood. People assume a higher grade means a better-looking diamond. Past a certain point it does not. This guide explains what inclusions actually are, which ones affect a stone and which do not, and the grade worth paying for. It is the companion to our full 4Cs of diamonds guide.
What are diamond inclusions?
A diamond forms under enormous heat and pressure, whether in the earth or in a lab. As it grows, it traps small irregularities inside itself: a pocket of another mineral, a tiny fracture, a wisp of unformed carbon. Those internal features are inclusions. Features on the surface, such as a scratch or a polish line, are called blemishes instead. Together they make up a diamond's clarity.
The useful thing to understand is that inclusions are normal. A diamond with none at all is so rare that it carries a premium most people never need to pay. Every inclusion is also unique, which is why graders use them like a fingerprint to identify a specific stone on its certificate.
Clarity is graded under 10x magnification by a lab such as IGI. What looks dramatic through a loupe is very often invisible once the diamond is held at arm's length, and that gap between what a grader sees and what you see is the whole key to buying clarity well.
Common inclusion types
Not all inclusions are equal. Some are harmless and visible only under magnification; a few, in rare cases, can affect how a diamond catches light or how durable it is. These are the ones you will see named on a grading report.
| Inclusion | What it is | Does it matter? |
|---|---|---|
| Crystal | A small mineral or diamond crystal trapped inside the stone | Only if large or dark enough to see |
| Feather | A tiny internal fracture that looks feather-like | Usually no; a large one near the surface can affect durability |
| Cloud | A cluster of microscopic pinpoints grouped together | Only if dense enough to soften brilliance |
| Needle | A long, thin crystal like a sliver | Rarely; usually invisible |
| Pinpoint | A single tiny crystal, the most common inclusion of all | No; essentially never visible |
| Twinning wisp | A ribbon formed where crystal growth shifted direction | Rarely; more common in lab-grown and fancy shapes |
| Cavity / indented natural | A small opening or dip at the surface | Sometimes; can catch dirt and is worth avoiding |
Two things decide whether an inclusion matters: its size and its position. A small crystal tucked under the crown where facets scatter light is easy to hide. The same crystal sitting directly under the table, the large flat facet on top, is the hardest place to disguise. A good grading report maps the location of each inclusion, so you can tell a stone with a central inclusion from one whose flaws sit near the edge, where the setting will cover them.
Eye-clean, explained
"Eye-clean" is the term that matters most and appears on no certificate. It means a diamond with no inclusions visible to the naked eye at normal viewing distance, roughly 10 to 12 inches away. A stone can be eye-clean and still show inclusions under a loupe. That is the point: nobody looks at your ring through a loupe.
Because eye-clean is about what you can see rather than a fixed grade, the grade at which a diamond becomes eye-clean changes with its size and shape. A half-carat round is eye-clean at a lower grade than a three-carat emerald cut, because the bigger, more open stone gives an inclusion more room to show. This is why buying by grade alone wastes money: you can overpay for a flawless certificate, or underpay and get a visibly included stone, depending on the shape.
The honest version of clarity advice is this. Above eye-clean, every extra grade is paying for something only a machine can see. Below it, you are looking at the flaw every day. The whole skill is landing exactly on eye-clean for the shape you have chosen, and no higher.
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Which clarity grade to buy
Labs grade clarity on an 11-step scale from Flawless down to Included. Here is the full scale, and where eye-clean typically falls.
| Grade | Meaning | Eye-clean? |
|---|---|---|
| FL / IF | Flawless / Internally Flawless | Yes, but you pay a rarity premium |
| VVS1 / VVS2 | Very, very slightly included | Yes; inclusions are hard to find even under a loupe |
| VS1 / VS2 | Very slightly included | Yes; the sweet spot for most buyers |
| SI1 / SI2 | Slightly included | Often at SI1; check SI2 stone by stone |
| I1 / I2 / I3 | Included | Usually no; inclusions visible to the eye |
For a round brilliant, which hides inclusions well, VS2 or SI1 is almost always eye-clean and is where we point most buyers. For brilliant-faceted fancy shapes such as oval, pear, marquise and cushion, VS2 is a safe target. Step cuts behave differently and deserve their own note.
The step-cut caveat. Emerald and Asscher cuts have long, open facets and no sparkle to break up the view, so the eye travels straight into the stone. They show inclusions far more readily than a brilliant cut. For these two shapes, step up to VS1 to stay safely eye-clean. It is the one case where paying for a higher grade is worth it.
Our full diamond quality chart shows how clarity sits alongside cut and colour, so you can balance all three rather than overspend on one.
Do lab-grown diamonds have inclusions?
Yes. This surprises people who assume a diamond grown in a controlled lab comes out perfect. It does not. A lab-grown diamond is a real diamond grown under the same heat and pressure, and it traps inclusions as it forms in the same way a mined one does. They are graded on exactly the same clarity scale by the same labs.
The difference is in the type. A mined diamond's inclusions are usually mineral crystals and feathers. A lab-grown diamond's are more likely to be metallic flux, a trace of the metal used to grow it, or faint twinning wisps from the growth process. Metallic inclusions can look dark under magnification, which is one more reason to buy eye-clean and to read the report rather than the grade alone.
In practice, high-clarity lab-grown diamonds are more available and more affordable than their mined equivalents, so reaching a clean VS grade costs less. Every Riona diamond is IGI-certified, so the clarity grade and the inclusion map are independently verified, not our word. If you want the detail on how to read that report, see our guide to diamond certification.
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Every Stone Certified and Eye-Clean
Every Riona ring is IGI-certified, conflict-free and made to order in solid gold. We help you land on the clarity grade that looks flawless without paying for a grade you cannot see.