Well, the answer might be obvious. The highest clarity is the best, but there is a lot more here to unpack. Want to know why flawless might be treated the same as internally flawless? Or what the term “eye-clean” really means in terms of diamond clarity?
What Do I Need to Know About Each Clarity Grade?
FL - the absolute queen of clarity
Well, it is kinda obvious Flawless or abbreviated as FL is the best clarity grade. Flawless is defined as both free of internal inclusion and external blemish on the surface of the diamond under 10X magnification. Flawless diamonds represent less than 1% of all diamonds mined and really are a perfect marriage of the natural world and human craftsmanship. Is this the whole picture? Just as Elsa might be the queen of Arendelle, it is actually her sister Anna who gets the most screen time. The same can be said about FL and IF diamonds.
IF - the queen's twin sister
So what about internally flawless? Internally flawless or abbreviated as IF is defined as no internal inclusion and only minor surface blemish present in the stone. Statistically speaking FL stones are going to be rarer than IF stones for sure. So, it may surprise you that within the industry both FL and IF stones are actually treated as the same thing. How come?
As a loose stone, an FL diamond ready to be sold as a loose stone will have to be inspected by a gemologist and then set into jewelry. There are plenty of opportunities to accidentally damage the stone and turn an FL into an IF diamond. On the other hand, you can touch up an IF stone on a polishing wheel and end up with an FL stone. But you still have to submit that stone to GIA again and get it re-certified. So in the industry, FL and IF are pretty much interchangeable when you are purchasing loose stone. They are pretty much all treated like IFs. Much like Schrodinger's cat, you never know if the stone is flawless or internally flawless unless you check. So, most industry professionals don't bother all too much.
But this is not to say that it won't affect the pricing at the retail level. Flawless will always command a higher price if you ask a retailer to get you an FL stone specifically. So if FL is what you want all the power to you, but do keep in mind that the GIA report might reflect the stone in the ring.
VS2/SI1 - perfect as far as the eye can see
Why are these even here? Because a diamond's appearance is not the same as the quality. The 4C of a diamond that gets so much spotlight is the objective measure of a diamond's quality.
Will I Be Able to See a Difference Between Clarity Grades?
For appearance sake, clarity grades: FL, IF, VVS1, VVS2, VS1, VS2*, SI1* can all be called eye-clean, which means that you cannot see any inclusion with the unaided eye or no magnification. Clarity-wise, diamonds from FL all the way to SI can appear the same. But for SI and VS stones some precautions should be made.
For smaller stones under 1.00ct, this eye-clean range extends into the SI ranges, but it is usually safer to stay on the VS2 side to be safe. For larger stones above 1.00 ct, especially into the 2+ range, a few diamonds of VS2 quality might not be eye-clean. Thus for these stones, VS1 is the safe bet to have an eye-clean stone. So if a flawless look is what you are looking for, a stone from flawless to VS and sometimes SI should satisfy your need for the best bling.