Slightly Included 1
SI1 diamond prices.
SI1 stands for "Slightly Included 1" on the GIA clarity grading scale. Inclusions noticeable under 10x magnification. May or may not be visible to the naked eye depending on size and placement. Our analytics are based on 94,829 diamonds with SI1 clarity — 16,158 lab-grown and 78,671 natural.
SI1 by colour grade.
Based on 16,158 lab-grown diamonds.
Browse SI1 by shape.
Frequently asked.
What does SI1 clarity mean?
SI1 stands for "Slightly Included 1". Inclusions noticeable under 10x magnification. May or may not be visible to the naked eye depending on size and placement.
How much does a SI1 diamond cost per carat?
Based on 94,829 diamonds, SI1 lab-grown diamonds average £1,296/ct and natural SI1 diamonds average £3,275/ct.
Is SI1 clarity worth the price?
SI1 may have visible inclusions in larger stones, but offers significant value. Best for those prioritising carat weight or colour over clarity.