What Is the Best Diamond Clarity?
There isn't one best clarity, and the textbook answer of flawless isn't the useful one. Flawless is the highest grade, but for almost everyone it's money spent on a difference you'll never see. What matters far more is whether a diamond is clean to the eye, and that depends on the cut of the stone, the size, and where any inclusions actually sit. Two diamonds with the same clarity grade can look completely different in real life.
Here's how I actually guide clients through it, and it pairs closely with how I think about colour.
What Does the Diamond Clarity Scale Mean?
Clarity grades a diamond by its inclusions and blemishes, viewed under 10x magnification. The scale runs from Flawless (FL) at the top, through Internally Flawless (IF), Very Very Slightly Included (VVS1 and VVS2), Very Slightly Included (VS1 and VS2), Slightly Included (SI1 and SI2), down to Included (I1 to I3).
The key thing to understand is that this is graded under magnification. Many inclusions that a certificate records aren't visible to your naked eye at all, which is why the grade on paper and how the diamond actually looks are two different things.
What Is an Inclusion?
Inclusions are natural characteristics within the makeup of the diamond, formed when the diamond grew in the ground. They vary in shape, size and colour, and that variation matters far more than people realise.
- Colour of the inclusion: a white or clear inclusion is much less noticeable than a black one.
- Position: an inclusion right in the centre of the diamond is far more visible than one towards the outer edge, which can be hidden under a claw or camouflaged within the sparkle of the facets.
- Depth: some inclusions are surface reaching, which means there's potential for the diamond to be damaged if it's knocked, or if a claw is pressed down with force on top of the flaw. That's a type I'm cautious about.
This is why a clarity grade on its own tells you almost nothing. A "good" SI and a "bad" SI can look identical on a certificate. It's only by inspecting the diamond in person that you can see what effect the inclusions actually have on how the stone looks and how light performs through it.
What Clarity Should You Actually Choose?
It depends on the cut, and the relationship is the opposite of how cut works with colour.
A brilliant cut, like a round or oval, hides inclusions in its faceting. A step cut, like an emerald, amplifies them, almost like a hall of mirrors, so any flaw is far more noticeable.
For a brilliant cut
VS is a great value option. I'd usually go for VS1 over VS2, because a VS2 can be visible to my very picky eye, though because I select diamonds by hand rather than from a certificate, I can make sure any VS2 I choose is genuinely eye clean. If you want to stretch your budget, you can drop to SI, as long as it's a good SI where the inclusions aren't really noticeable.
For a step cut
Go higher. I'd always suggest a VVS clarity for a step cut, so it sparkles as it should without the distraction of any imperfections. I wouldn't recommend trying to save money by lowering clarity on a step cut, because inclusions show so much more. If you want to stretch your budget on a step cut, go lower on colour instead, not clarity. (I cover that in my post on the best diamond colour.)
How Does Carat Size Change the Clarity You Need?
The usual advice is "bigger diamonds need higher clarity," but it really comes back to the location and colour of the inclusion.
A black inclusion in the centre of a large diamond will be more noticeable, because the table (the large flat facet in the middle) is bigger and makes it easier to see. But a white inclusion towards the edge can let even a large diamond appear clean to the eye. So size matters, but where the inclusion sits matters more.
At the small end, the diamonds used in something like a tennis bracelet are often much lower clarity than you'd use in an engagement ring, simply because they're small enough that inclusions are hard to notice.
So when budget is the question, it comes down to a choice: do you want the largest diamond you can afford while keeping it as clean to the eye as possible, or do you want a stone that's definitely free from any visible inclusions and accept slightly less size? Neither is wrong. It's about which matters more to you.
Why the Certificate Doesn't Tell the Whole Story
Almost everyone now buys clarity off a certificate, filtering a website for SI1 or VS2 and picking the cheapest one. The problem is what the certificate doesn't show.
A certificate can plot the location of the inclusions, but it doesn't show how close to the surface they are, and it doesn't show how an inclusion affects the performance of light through the diamond. So the cheapest stone at a given grade is often the cheapest for a reason.
By selecting a diamond individually by eye, I can make sure there are no hidden reasons you might not be completely happy with the stone in your bespoke ring. I'm particularly fussy about this. I regularly reject stones that other jewellers would happily accept, because I have my own high standards, and if I wouldn't be happy with a diamond for myself, I won't choose it for you.
So, What's the Best Diamond Clarity for You?
For a step cut, I'd always look for a VVS, so it sparkles as it should without any distraction. For a brilliant cut, I'd recommend VS1.
But the most important thing to remember is that clarity is only one part of it, and not even the most important. Make sure the diamond is well cut above all else. A D flawless diamond that wasn't cut well wouldn't look as good as an H SI diamond with an excellent cut. So don't agonise over chasing a high clarity grade. Decide whether size or absolute clarity matters more to you, prioritise a good cut, and choose a stone that looks right in person rather than one that simply reads well on paper.
That last part is what I help with. I hand-select every diamond by eye to my own high standards, so you end up with a stone that performs beautifully in real life, not just one that ticks a box on a certificate. If you'd like help finding yours, send me a message and we'll start there.
