Believe it or not, the bulk of diamonds in the market actually fall within the slightly included and included ranges. As the name itself suggests, slightly included (SI) diamonds have small imperfections and microscopic flaws in them.
Although the inclusions could be seen with ease using a 10X magnification loupe, SI1 diamonds will usually appear flawless to the naked eye of a casual observer. In fact, SI1 graded diamonds are great for people on a budget as they don’t have to compromise on cut quality to get a larger stone.
You could put a VS1 or VVS1 diamond beside an SI1 diamond and probably not tell the difference between the stones unless you examine them with a loupe.
In the SI clarity grade, you would usually expect to see inclusion types like clouds, carbon spots, pin points, twinning wisps or feathers (to name a few). What you really need to know is that even if two diamonds share the same exact GIA grading of SI1, they can look vastly different in real life.
Some diamonds may look totally eye clean and yet, some others might have flaws that would be noticeable immediately. Ultimately, the location, size and color of the inclusions play an important role in the face up appearance.
A grading report by itself will never be enough to make a judgment call on the diamond’s clarity and visual appearance. That’s why I always recommend shopping at vendors like James Allen or White Flash.
Both retailers offer high-definition videos of their diamond listings and enable you to see and scrutinize details in complete transparency. Here are two SI1 diamonds that are perfect examples of what to look for and I picked them out easily with the help of the video listings.
This D SI1 diamond has multiple colorless crystals that will appear invisible to the naked eye. While the inclusions are reflected around the diamond by the pavilion facets, the whitish color and tiny size make them a non-issue.
This 1 carat E SI1 diamond has a faint looking cloud and a small crystal under the table. Due to their size, they cannot be seen with the naked eyes and it makes the diamond eyeclean.
Now, there is also a large feather found on the pavilion side of the diamond which I would normally pay extra attention to. Since it will be hidden away from contact after the diamond is mounted on a ring, there’s no cause of concern.
1.00 Carat K Color SI1 Excellent Cut Round Diamond
Prongable diamonds are another kind of slightly included diamonds I would recommend. In this particular example, the feather is embedded within the body and also localized in an inconspicuous area.
When the loose diamond is viewed by itself, the feather is colored and visible to the naked eye. However, this inclusion can be completely covered up by a prong during the setting process.
When inclusions are found or congregated together under the table facet, it warrants proper scrutiny of the diamond for eyecleanliness. That’s what happened in the example below…
The size and location of the crystal inclusion make this diamond a poor choice. Besides being visually obvious, the crystal is also reflected into multiple images around the crown facets. By viewing the magnified photograph carefully, you should be able to pick out the faint reflections at the 3 o’clock and 5 o’clock arrow heads.
Now, if you were to take a look at its accompanying grading report, that is the only inclusion noted in the plot. If it wasn’t for this tiny crystal, the diamond would probably achieve an Internally Flawless (IF) grading instead.
Here are some other things you need to pay attention to. Very often, you will see comments in the GIA/AGS report stating “additional clouds are not shown” or “additional twinning wisps not show”.
Sometimes, these statements are non-critical issues and won’t impact the appearance of the diamond. At other times, they can cause diamonds to look hazy! Without physically seeing the diamond, you can’t really gauge whether this would be an issue.
Don’t rejoice too early if you think you found yourself a fantastic stone. The comments in this G SI1 diamond’s grading report is cause for concern. In such cases, it is best to have a gemologist inspect such diamonds or check the stone yourself.
In this example above, the additional twinning wisps have caused the diamond to become cloudy in its appearance. If you click on the image, it’s pretty easy to see this from the video listing. Obviously, this is a diamond you definitely want to avoid.
If you see a grading report of an SI1 diamond, it is an immediate RED FLAG. I know this may sound a little counterintuitive but you need to be extremely wary when things look “too good to be true”.
All 3 plots are suspicious looking by typical SI1 clarity standards. Avoid!
Where are all the inclusions? Why does the clarity plot looks like it is depicting a VS1 or VVS2 diamond instead? Instead, you will see statements like “Clarity grade is based on xxxxxxxx that is not shown” or “xxxxxxxxx not shown” in the comment section of the report.
Chances are, the diamond is going to look hazy or cloudy due to numerous un-plotted inclusions. You can see one such example in the video below where the diamond’s brilliance is adversely impacted.
The trick to buying great looking SI1 diamonds is to seek out those with inclusions that are well-spread out. If I am personally shopping for myself, I tend to look out for inclusions that blend well into the diamond’s body and I would stay away from inclusions found near the center of the diamond.
Keep in mind that you should NEVER buy a diamond in the slightly included ranges without eyeballing it. If an online vendor doesn’t offer you photographs or videos to inspect the stone, work with one who does.
The rule is simple: No photographs/videos, no talk. You don’t want to end up with an appalling looking diamond to remind you of the bad decisions you made.
To put your mind at ease, they also offer physical reviews performed by their in-house gemologists for free. What happens here is that they can call in your shortlisted diamonds from their suppliers to check for clarity related problems and the diamond’s optical performance.
At the end of the review, they will give you a report and synopsis to follow up on their findings. This will then enable you to make further decisions on buying the diamond based on tangible data.