SI1 and SI2 are the clarity grades for inclusions that are noticeable at 10x magnification.
In more detail
SI inclusions are easy to find at 10x, and sometimes you can see them by eye. Many SI stones still look clean at arm's length, so SI is a popular range. SI2 is the last grade before the included range.
On a grading report
Written SI1 or SI2 in the clarity grade line.
Related terms
- Very Slightly Included (VS1, VS2): VS1 and VS2 are the clarity grades for small inclusions that a grader finds with some effort at 10x magnification.
- Included (I1, I2, I3): I1, I2 and I3 are the lowest clarity grades. Their inclusions are obvious at 10x and can affect transparency and brilliance.
- Clarity grade: The clarity grade says how free a diamond is of inclusions (inside) and blemishes (on the surface) at 10x magnification. GIA's scale has 11 grades in six categories, from Flawless (FL) to Included (I3).
- Clarity plot: The clarity plot is the map on a full grading report: an outline of the stone with symbols on it. Each symbol shows the type, position and approximate size of a clarity characteristic.