SI2 — Slightly Included 2 on the GIA Diamond Clarity Scale
SI2 — Slightly Included 2 on the GIA Diamond Clarity Scale
The lower of the two SI grades, often eye-visible and the boundary with included stones
SI2 — slightly included 2 — is the eighth of eleven clarity grades on the GIA diamond clarity scale, sitting between SI1 and I1 (Included 1). The grade covers stones with inclusions that are easy to see at ten-power magnification and that are often, though not always, visible to the unaided eye. SI2 marks the practical boundary between near-eye-clean diamond and visibly included diamond, and the value of the grade in the retail trade depends almost entirely on whether the specific stone in hand is eye-clean from the face-up view.
What an SI2 inclusion looks like
SI2 grades typically carry larger, darker, or more numerous inclusions than SI1. Common SI2 features include centrally located dark crystals, larger feathers, larger clouds reducing transparency, and combinations of features that together would be insufficient for SI1. A skilled grader considers each feature against the GIA reference standards and assigns the grade based on overall impact, with attention to whether features approach the durability threshold that defines I1. An SI2 should not contain features that materially threaten the stone's durability; if they do, the grade falls to I1 or below.
Eye-clean versus eye-visible
The SI2 grade is the most eye-cleanliness-sensitive grade on the scale, in the sense that two stones with the same paper grade can have markedly different visual impressions. A central dark crystal will typically be visible at arm's length on a one-carat round; the same stone with a feather under the crown facets may pass the eye-clean test entirely. Photographs and clarity diagrams on the GIA report give an indication, but the only reliable test is the stone itself under normal lighting. Buyers of SI2 stones should expect to evaluate each piece individually rather than buy from paper grades alone.
In the trade
SI2 is the value entry point on the GIA scale for buyers who want a graded diamond at a price meaningfully below SI1 and who are prepared to do the eye-clean evaluation themselves or accept that the stone may show its inclusions. Wholesale price guides typically show a fifteen-to-twenty-per-cent step from SI1 to SI2 in commercial sizes, widening at the carat-and-above end where centrally located inclusions are harder to disguise. Step cuts (emerald, Asscher) are particularly difficult to find eye-clean in SI2 because the long open facets reveal any disturbance.