A diamond clarity chart is a standardized guide that grades a diamond based on its flaws, inclusions, and any other imperfections.
Any imperfection inside a diamond is called an inclusion (they are created when the diamond was forming) while imperfections on the outside of a diamond are called flaws.
Cutters will try to remove all the flaws possible and even cut the stone into a different shape in order to create a better grade diamond.
Inclusions on the other hand cannot be removed since they are on the inside of the stone and are often used to determine whether or not a diamond is real or if it's been treated in some way.
Inclusions are like a diamond's fingerprint... and no two are alike. The only real problem with inclusions is that they can limit the ability of light to pass through the stone.
Since diamonds are formed within the earth under intense pressure, imperfections are likely to occur. Most diamonds have a flaw of some sort—it's rare to find one without any—so, the fewer the imperfections, the rarer and more valuable the diamond. It makes sense!
Check out this video if you want to learn more about inclusions and GIA's diamond clarity scale.
Think of an inclusion as a beauty spot. They bring character to the stone and can make a diamond uniquely beautiful (like Cindy Crawford's facial beauty mark). The only difference is that in a diamond's case, many of the inclusions are invisible to the naked eye.
The rating system for diamonds, when it comes to clarity ranges from flawless to imperfect (or included) with various grades in between. When looking at the chart always keep in mind that what is being shown is based on what can be seen under magnification.
Flawless diamonds are very, very rare, even most jewelers haven't ever seen one.
As you progress from left to right on the diamond clarity chart you begin to see more imperfections (or beauty marks) in terms of inclusions. Remember these stones are being viewed through 10X magnification so most of the inclusions you see in the chart would not be visible to the naked eye.
Anything from VS-1/VS-2 left, are really minor imperfections. From that point on, the further you go to the right on the clarity chart the more likely that the imperfections may be seen by the naked eye and start effecting the brilliance and transparency of the stone—which in layman's terms means less bling!
However, not all inclusions are equal and some will have much less of an effect than others.
Engaging Tip: Contrary to popular belief, higher clarity does not always mean more beautiful. If the inclusions are not visible to the naked eye, a higher clarity does not significantly improve the appearance of a diamond—just the rarity and price.
The GIA scales help us compare one diamond to the next and are a great guide for diamond shopping. Now when a jeweler talks about the diamond clarity, or you see it in a grading certification report, you'll understand what they are referring to and what it all means.
Now the most important of the 4Cs: Diamond Cut.