SI1 clarity

SI1 means slightly included: marks are noticeable at 10x.

Grade: 7th of 11, between VS2 and SI2
In nature: Common in jewellery: most shop diamonds are VS or SI.
In RXXO: 1 in 9 diamonds

SI1 in RXXO

325diamonds like this in RXXO right now

Questions

What does SI1 mean on a diamond?

Slightly included. Marks are noticeable at 10x.

How rare is an SI1 diamond in RXXO?

About 1 in 9. The most common grade is I3, about 1 in 5.

Is SI1 better than SI2?

Yes, by one grade. SI1 sits just above SI2 on the 11-step clarity scale. In RXXO, an SI1 is about 1 in 9, an SI2 about 1 in 8.

RXXO numbers are the odds every mint draws from. Updated 8 October 2026.