SI1 Diamonds – Can Be Flawless to the Naked Eye!

Your eyes didn’t fool you when you read the title. It’s not a meatless clickbait either. The bottom line is, you can find beautiful SI1 diamonds and I’m going to show you how!

If you’ve read my post on how VS2 is the clarity grading win zone, you must be wondering why SI1 – another grade lower – can be just as good. Well, it’s true that VS2 is the sweet spot because it’s a safe bet. You don’t have to tread the waters of the SI range to find an eye clean diamond.

But since we’re all about getting the biggest bang for the buck, you can still go a notch lower in the clarity grading. You just have to arm yourself with the shopping tips below.

In this post, you’ll learn how to pick an SI1 diamond that will look spotless to the untrained eye. By the time you’re down on one knee, SI1 will simply look immaculate to her. And when it’s time to show off the ring, let’s just hope none of her friends carry a 10x magnification loupe with them. Because that’s the only way you’ll see SI1’s flaws!

Sl1 – Slightly Included 1

As the name suggests, SI1 diamonds have small inclusions that are easily seen under 10x zoom, but not noticeable with your bare eyes especially through a casual observer’s eyes.

Diamond Clarity Grading

The flaws in this grade are readily visible to a gemologist when the diamond is assessed with a 10x loupe – the definitive tool for rating diamond clarity. This may sound strange, but a huge sum of diamonds in the market are actually SI and I stones. SI1 diamonds are priced way lower, but that doesn’t make them less beautiful – given that they’re eye clean.

Eye Clean and Not Eye Clean SI1 Diamonds

Diamonds in the SI range usually possess clouds, feathers, pin points, twinning wisps, and carbon spots. (Read more about inclusion types here!) Although these inclusions vary in different aspects making two SI1 diamonds look completely different.

Just take these diamonds for example:


They have the same 4Cs, but without seeing these magnified images, you wouldn’t know which is eye clean or not. Then again, no two diamonds are alike, so this isn’t always the case for eye clean and not eye clean SI1s. There are actually other factors to see if your gem is flawless without loupe!

How to Score an Eye Clean SI1 Diamond

1. Consider the Diamond’s Size and Shape

Double check if your stone has the right carat weight and shape to suit a SI1 grade. Truth be told, not all diamond shapes can be eye clean SI1s. Round, princess, and radiant cuts can hide inclusions with their brilliance, but asscher and emerald cuts bear large tables that can illuminate flaws.

  • Same thing with 2-carat diamonds or larger as they have bigger facets that make it more difficult to hide inclusions. In short, you won’t get away with SI1 if your diamond is a step cut or considered big by average women like a 3 carat diamond. You’re better off with a VS1 or VS2 clarity grade.

    However, if this is not the case, we can then move on to one of the most important factors.

    2. Make Sure Your SI1 is Graded by GIA or AGS

    GIA Diamond Grading Report

    I would always recommend the only reliable labs in the US – GIA and AGS. It’s good to make sure your pick is graded by a reputable lab because they will tell it like it is.

    If they grade your diamond as SI1, then no other labs, companies, or vendors can change this rating. They’ve spent millions of dollars to assure the quality and accuracy of their equipment, so you can bank on their reputation.

    Some would argue that IGI and EGL are also legit, I’m not saying they aren’t, it’s just that they rate a diamond 2 to 3 grades higher than what it should be. So, when you see a SI1 diamond by EGL, it could probably be an Included diamond when graded by GIA, and you will most likely see inclusions.

    Although being graded by GIA or AGS doesn’t necessarily ratify that your diamond is eye clean. It’s just a safe seal that what you have is indeed a SI1 stone.

    3. View Diamonds in Magnified Photos and 360° Videos

    The only way to assure a flawless gem is to see it in super zoom. Gone are the days when there’s no other way to choose an engagement ring, but through a 10x loupe in a brick and mortar store.

    James Allen Zoom

With today’s latest technology, everything is at your fingertips. We are now able to view, compare, and purchase diamonds online. And it’s totally safe!

But given this modern age tool, there are still some people who would solely rely on grading reports and buy blindly. As for you, since you like knowing what you’re getting into, there are a few trusted shops that show actual photos of their diamonds. And the one that’s currently on top of my list is: James Allen

Not only do they offer magnified imagery and intuitive videos, they also have in-house gemologists that can review your diamond for free. They’re diamond display technology is the only one of its kind.

Now,we keep saying “find an eye clean diamond”. But what really constitutes an eye clean gem?

4. Watch Out for the Inclusions’ Size, Color, and Location!

If being ‘not eye clean’ means seeing inclusions, then ‘eye clean’ must mean there are no flaws at all, right? Well, not really. An eye clean diamond can possess visible inclusions, but depending on the three major factors that affect the gem’s face up appearance – size, color, and location.

The trick is to find a diamond with very small inclusions that blends with its body color, and are well-spread out because inclusions at the center tend to be the most evident.

Here are the grading reports of the eye clean and not eye clean SI1 diamond examples from above:

Eye Clean SI1 Diamond Plot vs Not Eye Clean SI1 Diamond Plot

Now, the diamond on the left is what I mean by inclusions located away from the center. You can barely make out the inclusions because of the size and light color. The second diamond on the right side, aside from having pretty obvious flaws, they’re also too compressed which intensifies their visibility even more. This is what you should definitely avoid!

The tips above will guarantee that you’ll find a legit and eye clean SI1 diamond!


Here’s a Bonus Trick for Your Viewing Pleasure:

Readers often consult me about the inclusions they see under 20x or even 40x magnification on James Allen. Well, obviously, you can easily make out inclusions in this level of magnification.

In fact, with a 40x zoom, you’ll even be able to see minute inclusions in IF diamonds! The thing is, standard grading is always done with a 10x jeweler’s loupe, not with super zoom. So, how can the magnified images really assist you in knowing if a diamond is eye clean or not? It’s quite easy!

Have a look at these SI1 diamonds from James Allen:

        • James Allen eye clean SI1 diamond
        • James Allen not eye clean SI1 diamond
  • With the usual 20x zoom, both gems show visible flaws. The diamond on the left bears dark crystals under the table, while the one on the right contains a large and stark black inclusion at the center.

    Now, in order to replicate viewing in person, simply switch the magnification from x20 to x2:

    2x Magnification

    You might ask why x2 and not the least magnification. Well, this is the security margin where you can thoroughly evaluate the gem as you won’t really notice anything in x1.

    If you cannot make out an inclusion in a diamond at 2x magnification, it will be eye clean in real life. Although, just make sure that you are really turning down to 2x and not to 3x magnification. Try it with the diamond on the left, you’ll easily see that there’s no visible inclusions! And upon seeing the one on the right in 2x zoom, you’d clearly want to avoid buying that gem. But of course, some cases might be trickier than this.

    The Takeaway

    A one-time researcher wouldn’t have known that you can go low in clarity grade as long as the diamond is eye clean. This trade secret is only known to those who really do their homework, such as yourself. With the considerable amount of money you’re going to save, you may now opt for a larger diamond and a better cut! Or maybe save it up for the wedding rings. Treat yourself. 😉

    If you have any questions about SI1 diamonds, I will be more than happy to help you out. Just drop a comment below or write to me. My advice is free!