Diamond Clarity Grade

Like the Cut grade, the AGS Laboratories’ reports come with numeric and verbal descriptors for Clarity. The numeric system is the same as for Cut — from zero to ten, zero being the best.

The verbal descriptors are trade terms originally developed to describe diamonds for diamond manufacturers and retailers. Over time, these terms have become recognized at the consumer level as well, and because they are widely accepted, we adhere to them, too. 

The Grades are from highest to lowest in Clarity quality as follows:

Flawless/Internally Flawless (F/IF) — Very rare for diamonds!

Very, Very Slightly Included (VVS₁ and VVS₂) — Also very rare.

Very Slightly Included (VS₁ and VS₂) 

Slightly Included (SI₁ and SI₂) 

Included (I₁, I₂, and I₃)

The Story of SI₃
Over time, diamond manufacturers, retailers, and some laboratories adopted the term SI₃. This is supposed to represent a class of diamonds with a diamond clarity of between SI₂ and I₁. The AGS does not recognize this term. In our book, a diamond is either SI₁ or SI₂, and should be priced accordingly on the market. This is just one more way we keep your best interest — and investment — a priority.

Tips from the AGS Laboratories Rock Stars:

Diamond size has an effect on clarity. It’s easier to see an inclusion in a larger diamond than in a small one.
You might hear that only diamonds with Clarity grades of Included AGS 7, 8, 9 & 10 should have eye-visible inclusions. Truth is, some AGS 5 and 6 clarity stones or GIA SI₁ and SI₂ can have eye-visible inclusions, depending on your visual acuity and how hard you look.