Small Inclusions (SI1) (SI2) (SI3)
SI is the abbreviation for "small inclusions" which now become "easy" (SI1), very easy (SI2), and almost obvious (SI3) to see under 10x magnification. In some SI's the inclusions can be seen with the unaided eye.
While you can pretty much expect what to see under a scope when you look at stones that are VVS and VS (really tiny imperfections), the SI clarity grade can range from quite a spectrum as there is more to see. The SI1 grade is still a pretty descent looking stone from the perspective of "under the scope", but when you get into the grade of SI2 and then even SI3... well let me say this: Not all SI2's are created equal. Diamonds become less rare as we move down the clarity scale. This clarity grade is probably the most popular (in brilliant cuts) for 2 reasons:
- The stone is still an "eye clean" diamond.
- The price difference between SI's and VS's is quite a jump!
When the expression "eye clean" is used, this means observing the diamond "face up" as it is mounted in a ring and viewed from roughly half an arm's length in distance. If you take an SI clarity (and even some VS's) grade diamond and turn it face down, it is possible to see the imperfections (and/or even reflections of the imperfections) with the unaided eye. There's nothing wrong with observing a diamond upside down when you're inspecting it, but it could be an inaccurate representation of what the clarity really is.
Slightly Included category (SI) diamonds have noticeable inclusions that are easy to very easy for a trained grader to see when viewed under 10x magnification. The SI category is divided into two grades; SI1 denotes a higher clarity grade than SI2. These may or may not be noticeable to the naked eye