When diamonds are naturally formed inside the earth, there is no quality control. The diamond grows in various phases, where the conditions have to be just right. There are no constants in the diamond formation process, the pressure is not always the same, and the temperature fluctuates through various levels, heating and cooling unevenly. It is because of all these nuances, these tiny details, that diamonds receive their internal features, or inclusions. How amazing is it then when we find diamonds that we call Internally Flawless (IF), or even Flawless (FL)!
Consider the current Gemological Institute of America diamond grading scale...
I - Imperfect
Diamond Clarity grades start at the bottom of the scale with Imperfect sub-group 3 (I3), which is highly included, throughout the diamond, with these inclusions very easily visible to the naked eye. It is not uncommon for these inclusions to be so large they threaten the integrity of the diamond, and at best diminish the brilliance of the diamond. Then, the next step up is Imperfect sub-group 2 (I2), where the diamond has numerous inclusions, easily visible to the naked eye. Again, the inclusions in an I2 diamond often diminish the brilliance of the diamond. The next step up, is Imperfect sub-group 1 (I1), in which case the diamond has inclusions, which are visible to the naked eye, and most likely at a minimum go through the middle of the diamond. The location of the inclusion begins to play a role in the Clarity grade, as most Imperfect diamonds are determined as such when examining through the crown, or the top of the diamond.
SI - Slightly Included
Above the Imperfect or "I" clarity diamonds are Slightly Included clarity diamonds, with two sub-groups. Slightly Included sub-group 2 (SI2) diamonds may have inclusions which can be seen with the naked eye, however, it will take a bit of time, especially for the untrained eye, to see anything without magnification. For many people, this is where fine diamonds begin. The next step up from SI2 diamonds are Slightly Included sub-group 1 (SI1) diamonds, which will usually have only a few, if any, inclusions visible to the naked eye, and these will take quite a bit of time to locate. Under magnification, these inclusions should be more easily discernible to the experienced eye. This is a very popular diamond clarity grade, as it has diamonds that are clean yet affordable, relative to their size, et cetera.
VS - Very Slightly Included
Moving up, the next diamond clarity grade is Very Slightly Included, and it has two sub-groups. Very Slightly Included sub-group 2 (VS2), which has very small internal defects that can be seen through magnification, by an experienced expert, with some difficulty. The next step up from VS2, is Very Slightly Included sub-group 1 (VS1). The distinguishing factors between VS2 and VS1 are the size, position and number of the internal defects of the diamond.
VVS - Very, Very Slightly Included
It almost is silly, the name of the next step up from VS quality diamonds. Very, Very Slightly Included has two sub-groups, and is where magnification is a requirement for clarity grading. Very, Very Slightly Included sub-group 2 (VVS2) have very, very small internal defects, which require 10x magnification, and an experienced expert, to locate, with considerable to great difficulty. The next step up from VVS2, is ... wait for it ... Very, Very Slightly Included sub-group 1. The distinguishing factors between VVS2 and VVS1 are again, the size, position and number of the internal defects of the diamond. For the very discerning, this is where fine diamonds begin. Keep in mind, VVS1 is a no joke, a very, very clear diamond, especially when you consider the next step up from VVS1.
IF - Internally Flawless
Internally Flawless diamonds are cut diamonds which are absolutely free from internal defects or faults, tested by very experienced experts under 10x magnification. (Note, that was "experts," plural.) Even though this is "Internally" Flawless, any external features should be so tiny that they can easily be removed by polishing with very little loss of weight. There is only one diamond clarity grade higher than Internally Flawless.
FL - Flawless
Flawless diamonds are cut diamonds which are absolutely free from both internal and external flaws, tested by very experienced experts under 10x magnification. There is no higher diamond clarity grade than Flawless. This is the pinnacle of diamond clarity. You have arrived.
Remember the totally chaotic journey diamonds must undergo while they are forming. There is no quality control ensuring the pressure or temperatures or mineral mixes are to specification. And with so many variables, to happen in nature, the rarity of encountering an Internally Flawless, or even moreso a Flawless diamond, is amazing.
As of the writing of this, Diamond Rex does not have any Flawless diamonds in our inventory, though we can get them for you. We do have some Internally Flawless diamonds! And of course, as with all of our diamonds, they have already been sent to the Gemological Institute of America Laboratories to be independently graded.