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SI1 Clarity Diamonds

SI1 of Slightly Included represents the top 10% of all the world’s diamonds user for engagement rings. SI is the range where the most value is derived in terms of price and quality. There is generally a large difference in diamonds between VS and SI because it is often the difference between eye visible and non-eye visible inclusions. We generally recommend SI diamonds only if the grade isn’t set by a single, larger eye visible inclusion such as a black crystal in the center under the table facet. The most common SI inclusions are crystal, feather, indented natural, twinning wisps, needles, and clouds.

What is an SI1 Clarity Diamond

SI1 or Slightly Included 1 diamonds have inclusions that are noticeable under 10x magnification by a trained gemologist. These diamonds may have 1 inclusion that is eye visible, but generally the inclusions cannot be identified, unless magnified.

What to avoid in an SI1 Clarity Diamond

You should avoid diamonds where the clarity grade is set by a cloud or a single large inclusion. In the SI1 range, there are a large number of inclusion types that may be present in the diamond. Generally, if the diamond has a cloud that sets the grade, it will often look hazy or milky. The cloud is large clusters of pinpoints that white out of wash out the diamond. If this occurs, light is unable to pass through and reflect back and so the diamond look dull. SI1 diamonds with cloud inclusions often have discounts and so it’s never a good idea to just purchase the least expensive SI1 diamond based solely on its price. Further, GIA does not plot the cloud on the diamond plot in the grading report. Therefore, it will look like a completely clear diamond even though it isn’t.

Additionally, you’ll want to avoid a single, large inclusion such as a crystal. These crystals are formed naturally during the diamond’s growth process and are often black in color. A black crystal is visible in white light. It can often be eye visible and will distract from the diamond’s beauty.

How to Buy an SI1 Diamond

There are SI1 diamonds that present good value and have small inclusions not visible without magnification. A single feather inclusion is often okay though because it is less visible. Consider diamonds with twinning wisps (streaks of smaller imperfections) or inclusions off to the side of the diamond. There are times where you’ll find diamonds with impurities on the edges near the girdle that can be covered by prongs when set in rings or jewelry. Those are the most prized and desirable. Also remember that the larger the diamonds the larger these imperfections look. In diamonds in the 0.70ct or below range, don’t worry about the visibility of the clarity grade. In 1.00ct or greater, it may be more visible or prevalent.

If you’re thinking about the differences between SI1 and VS2, we recommend VS is you can squeeze it into your price range. SI diamonds often have eye visible inclusions that may bother you so you’re better off safe than sorry as you will be wearing this diamond for life. See examples of VS2 and SI1 diamonds below and you be the judge.

10x zoom magnified diamond example, typical for diamond clarity grading
10x zoom
10x zoom with I1 clarity inclusions
10x zoom with SI2 clarity inclusions
10x zoom with SI1 clarity inclusions
10x zoom with VS2 clarity inclusions
10x zoom with VS1 clarity inclusions
10x zoom with VVS2 clarity inclusions
10x zoom with VVS1 clarity inclusions
10x zoom with IF clarity inclusions
10x zoom with FL clarity inclusions
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