Clarity refers to the tiny, natural imperfections that occur in all but the finest diamonds. Gemmologists refer to these imperfections by a variety of technical names, including blemishes and inclusions, among others. Diamonds with the least and smallest imperfections receive the highest clarity grades. Because these imperfections tend to be microscopic, they do not generally affect a diamond's beauty in any discernible way.
No internal or external imperfections. Internally Flawless: No internal imperfections. Very rare.
Very difficult to see imperfections under 10x magnification. An excellent quality diamond.
Imperfections are not typically visible to the unaided eye. Less expensive than the VVS1 or VVS2 grades. Popular choice.
Imperfections are visible under 10x magnification, and may be visible with the unaided eye. A good diamond value.
I1 diamonds have inclusions that are almost always visible to the naked eye. Because I2-I3 diamonds have prounounced inclusions they are not suggested by Diamond Jewelry from Antwerp.
If you cannot tolerate imperfections, even those you cannot see, choose a VVS2 or better diamond. About 10% of all diamonds sold fall into this category.
The most popular range is the VS1-VS2 diamond. These diamonds appear flawless to the naked eye, and are a fraction of the price of a truly flawless diamond. Almost half of all diamonds purchased fall into this range.
The next most popular range is SI1, where the inclusions are usually not significant enough to impact the appearance of the diamond for the casual observer. Often, customers will opt for this clarity range in exchange for a higher cut or color grade. This combination often results in a beautiful, lively diamond with imperfections detectable only upon close inspection.
If you are primarily concerned with size and price, I1 may be your best option. While the inclusions are visible to the unaided eye, many customers find it to be well worth the sacrifice for what it affords in size.