Between all diamond clarity grades, the SI1 (slightly included) is the most controversial one, some say it has a lot of inclusions that you can identify with your naked-eye, others say it’s considered an eye-clean grade! And others are between this and that!

These two diamonds you see here are identical in terms of general characteristics (4Cs, polish, symmetry), they both have SI1 clarity grade:

Two SI1 diamonds

Unbelievable, isn’t it?

Take a 20x or even 40x look on both of them, here is the first one to the left, and this is the one to the right, why the difference? If we know why, we can then understand why the SI1 is very problematic grade for a lot of people.

This post will be discussing everything you want and should know about SI1, we will see if it’s a good grade to buy, when to buy it, when to avoid it, and when you can make a good deal by getting one!

Why Higher Clarity Grades Are Insanely Expensive?

We know that finding the right diamond for you or your loved ones requires that you have at least, the basic understanding of the different types of diamonds on the market, and their characteristics.

While diamond market experts would easily tell you that the best diamonds are the flawless (FL) & internally flawless (IF) diamonds with no inclusions at all, they may not also readily state that there are good diamond clarity alternatives.

Look at this image, for example, this is an Internally Flawless TrueHearts diamond on James Allen, priced at $30k, which is almost DOUBLE the price of the same characteristics for a VS2 difference (like this one):

Flawless TrueHearts

If you open the diamond link and see it under 360 HD images or 40x superzoom that James Allen provides, you will not be able to detect any inclusion, and that’s what flawless means.

Flawless & Internally Flawless diamonds are very rare, they both sum up to almost 3% of diamonds globally, and that tells us why they are so expensive!

But does this mean that to get a clean diamond, you have to go to that level? 

Many people have had to ignorantly spend way higher than their normal budget, even when they could have gotten something that is still validly good for their intended purposes- and for a lesser price.

Now, although the best diamonds sometimes are worth investing your money on, you could also get other diamonds with some bit of imperfection that does not, however, spoil the fundamental expectation of what people want in a sparkling diamond, at all.

What is SI1 Clarity Grade? And Why it Attracted a Big Attention?

SI1 clarity grade stands for Slightly Included, and this refers to the inclusions found on the diamond, whether it’s visible to the eye, or not, the amount & types of inclusions both determines if a particular diamond is SI1 or VS2.

The diamond clarity SI1 has seemed to become one of the most adopted diamond clarity grades in recent times. But then, what you essentially need to know about the diamond clarity SI1 category, is that they are also confirmed to have clarity blemishes.

Blemishes don’t necessarily mean visible inclusions, and even with visible inclusions, sometimes these inclusions are hidden by the setting and don’t affect the light reflection at all.

That’s why it’s even harder f`or a lot of people to tell if an SI1-graded diamond is a good one to go, since there is no one rule for all SI1 diamonds.

Since the clarity levels of a diamond specimen are a great determinant of its aesthetic value and overall beauty, the question of whether the SI1 clarity category is a good option to buy becomes a really valid one.

It is important for prospective diamond buyers to understand the facts so that their buying decisions are more informed and more guided.

Diamond Clarity Grades and Where the SI1 Grade Falls

Although in the real sense, diamond clarity levels are categorized into about eleven individual groups as they appear in the image below, we can group them into two broad classes: Eye-clean, and Visible Inclusions.

This is not an official grouping at all, it’s just for the sake of having a quicker and better understanding.

Note: SI3 level is not adopted by major certification labs like GIA, it was introduced by EGL for the sake of sellers, not buyers, read here how & why.

Note, however, that these two category grouping only follows when you’re considering the clarity of diamonds using the naked eyes only. According to the results obtainable when you view the samples under the standard 10× magnification, you’ll get the original eleven groups.


Following the naked eye view classification of diamond clarity levels, we have the following:

  • Diamonds without visible blemishes (Eye-clean)
  • Diamonds with visible blemishes (Not eye-clean)

Some diamond analysts and experts say it is better not to go for diamonds with blemishes. What this means in summary, is that the flawless diamonds are the most ideal diamond recommendation.

This is a very top-level recommendation, like saying “the ideal car is Tesla or Lexus” for example, yes that might be true, but it’s not necessary for everyone to follow this, more on this below, keep reading.

Diamond Sparkle James Allen

Diamonds with blemishes have reasonably reduced aesthetic appeal- depending on the amount of observed blemish- to the eye, in fact, know that the more blemish or less clarity on a diamond sample, the less valued it would be on the market. We cannot, however, restrict our diamond use specifications to the FL, because of a list of factors including the huge price traits.

For example, THIS diamond on JamesAllen is 1.01 Carat, F color, excellent cut, for around $10k because it’s Flawless clarity, while this almost EXACT diamond, but with a lower clarity grade, a VS1, is 40% cheaper than the first one ($6410).

The price difference you’re paying here is for something that you can NEVER tell by looking at the diamond in your naked eye, and you can save more if you go a little lower as well, let’s see to which grade we can stay “safe”.

This is where diamond clarity classifications based on a clean eye view, comes to bear.

Why you Should Look for Eye-Cleanness Rather than Clarity Grades?

If you want a 100% eye-clean diamond, then you can safely get a VS2, if you don’t care about having visible inclusions (we doubt), then SI2 will be the cleanest grade WITH visible inclusions.

Between both, the SI1 comes to tell us that it’s neither eye clean all time, nor it has inclusions that you can see by your eye! What the point here then? The point is to get the best bang for your buck! And understand when you can get an SI1 without any visible inclusion!

It is concluded that as long as the impurities cannot be easily seen with the naked eye, the diamond sample would still retain good aesthetics. Diamond clarity SI1 (most of them to be accurate) falls under the ‘diamonds without visible blemishes’, so this is an initial good sign.

What this means is that even if you place a superior clarity diamond side by side with an eye clean SI1 diamond, it’s not impossible to think that they’re of the same clarity levels.

Blue Nile Ring 2

Actually, SI1 diamonds are the intermediate between diamonds with visible inclusions and those without. Hence, there may be several times when they would appear with little visible inclusions too, but this is not so common.

The good thing about this clarity level is that their inclusion ratios- when visible to the naked eye, are significantly small and would not affect the diamond sparkle in any big way.

Consequently, SI1 diamonds may be a good option for you- if you’re on a moderate budget, and still do not want to sacrifice that important brightness and sparkle.

Read: Diamond Inclusion Chart – How it Affects Clarity?

How & Where to Find an Eye Clean SI1 Clarity Diamond?

Sometimes, the issue with buying diamonds based on clarity levels is the fact that you cannot always determine for sure if what you’re buying is actually true to stated specifications.

Don’t expect that there are no fraudulent sellers on the diamond ornament market- who would pose diamond products of lesser clarity and claim them to be what they’re not.
When people lose money in the diamond trade, this is, in fact, one of the main reasons why.

How to guarantee an eye-clean SI1 diamond?

Always look for a magnified image and a certificate. If you’re at a local store, don’t just look at the diamond with a 50 cm distance between your eye and the diamond to determine cleanness, get closer, and try to look.

If you’re not able to tell any inclusion, check its certificate, for GIA certificates (for diamonds with +1 carat), you will  see this clarity section:

GIA Clarity section for VVS2 diamond

After you see inclusions locations on the certificate, try to find them with your eye on the diamond itself, if you can’t then it’s 99% you’re looking at an eye-clean SI1 diamond (and that’s why we always recommending GIA certificates as a first choice).

If you’re in an online store like James Allen or Whiteflash then you’re covered, you have 360-HD images for diamonds, you can rotate the image, zoom in 20x (and on James Allen, you can even go 40x with Superzoom technology).

But one important thing to note here, in 90% of cases, you will be able to see most inclusions on the diamond, but remember that you’re inspecting a magnified image, to make it more realistic, zoom out until you feel you reached the real diamond size, and then try to see the inclusion!

This way, you can be 100% sure of getting an eye-clean SI1 diamond, and you got the best bang for your buck, without investing more money in something that you will not be able to tell.

Now to the next question:

Where to buy an eye-clean SI1 Diamond?

What we actually advise is to buy diamonds online, yes, while a lot of people prefer to see a diamond and would never consider getting it online, the biggest names like James Allen & Blue Nile have introduced a 360 degree zoomed view for their diamonds.

We’ve also mentioned Whiteflash, the house of A CUT ABOVE® premium diamonds, Whiteflash website allows you to see all their inhouse diamonds with 360-HD images as well, using a great imaging technology!

Whiteflash 360 HD Diamond Videos 970x250 (1)

Read: JamesAllen Vs. Blue Nile – Full & Detailed Comparison

Read: The Superior Quality Diamonds Store Whiteflash Detailed Review!

Buying online will rest-assure you that you’re getting what you’re seeing, to read further about this, and what are the pros of buying diamonds online, we refer you to our guide here on Where to Buy the Best Diamonds Online.

Other Important Factors When Getting SI1 Diamond

Another thing to consider when buying an SI1 clarity diamond is the dispersion ratio of the inclusions. SI1 diamonds would usually contain either or all of carbon spots, clouds, feathers and pinpoints, etc. All diamond clarity grades except the FL class contains these blemishes in varying ratios. The more clustered the inclusions on the gemstone, the more conspicuous it becomes.

The inclusions in the SI1 diamond would reasonably become inconspicuous, if the inclusions are not gathered up on one spot, or close to the diamond table of the sample.

If you discover that the inclusions on an SI1 diamond are found just beneath the diamond table region, then you may essentially need to find another diamond product to buy.

Asides these, authentic ratings from such organizations like the Gemological Institute of America (GIA) or the American Gem Society (AGS), are some other important things to ask for.

In fact, it is recommended that you only accept a diamond clarity rating issued by either of these organizations or the few other alternatives like IGI (and run away from EGL diamonds). If you’re shopping from an online store, make sure you’re provided with sufficient visual proofs that could help you confirm.

When NOT to Get SI1 Grade? Carat Effect on SI1

In general, what you’re concerned about in diamond clarity determination, is to ascertain the level of impurities and imperfections that are on a diamond sample. What we’ve seen above is a recommendation and general guidance to get a clean SI1.

To make a clear statement here, at some carat point, it’s recommended to skip the SI1 and go directly to VS2 to stay safe, and this depends as well on inclusion type & location on the diamond.

But if we want to generalize, we can say that after 1.3 carat, if your diamond has inclusions on the table, even if they are small, we don’t recommend SI1 on these cases, so play it safe, and go VS2.

This is because it is easier to spot the blemishes in a bigger diamond sample, than in a smaller one, we’ve explained this in more details in our Diamond Carat Chart Guide: How Weight Affects Size.

If you’re in doubt, and want to ask us about a particular diamond, please contact us through the form below, and we would be glad to offer you free help & consultation.

Going a level up to VS2 should be enough in most cases, and don’t get sold to a retailer who will be trying to convince you with a very high clarity grade for the sake of a higher Carat.

Bottom Line: Is SI1 Clarity Good Enough?

In a nutshell, any eye-clean diamond should be good for you to buy, most of SI1 clarity grade diamonds are eye-clean, you just need to make sure that any imperfections are not beneath the diamond table.

The other case is that if you’re buying a large diamond, more than 1.2-1.3 carat at least (in many cases and depending on inclusion type & location, it’s safe to go 1.5 carat), some inclusions can be seen on larger diamond even if it’s SI1.

In the above two cases, don’t exceed VS2 grade, VS2 is eye-clean in 99.9% of diamonds.

You may ask, I’m on a good budget, why shouldn’t I invest more in clarity? I want my diamond to shine more!

If you have more money, spend it on the CUT, it’s the most important factor in any diamond, got more money? Spend some on Color and then go for a higher clarity level.

Find the One James Allen

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