In diamond clarity, SI1 is the most controversial clarity grade, for the sole reason that there is no definitive agreement whether it’s 100% eye clean or not.

To a great extent, those who say SI1 is eye clean is much more closer to the truth, because that’s basically what differentiates SI1 from SI2.

For visual proof, do you believe that both of these diamonds are SI1?

SI1 eye clean and eye-visible

Here is the diamond on the left, nice, clear, and eye-clean SI1 on James Allen, and on the other hand, here is the right SI1 diamond (excellent cut as well), but has a lot of inclusions that you probably can see them with naked eye.

The debate seems valid here, so that’s why we need to learn a little more about the SI1 diamond clarity grade diamonds, their prices, how to find one, and best places to get a great SI1 diamond.

What are SI1 Diamonds?

Diamonds are formed under high pressure and temperature conditions deep within the Earth’s mantle. During the diamond formation process, impurities and irregularities can become trapped within the crystal lattice structure, resulting in imperfections or inclusions.

These imperfections can affect the diamond’s clarity and value, but they can also make each diamond unique and add to its character.

Pro Tip: Generally, it’s common to refer to any imperfection on the diamond as “inclusion”, while there is a main difference between inclusions & blemishes:
Inclusions are these birthmarks which are internal (haven’t reached the diamond surface), while blemishes are -obviously- external birthmarks (on diamond surface).

GIA, as the leader grading lab in the diamond industry, created a clarity grading chart to categorize/group diamonds into a scale of six categories and eleven grades based on how visible inclusions are in a diamond.

SI1 diamonds as per the official standards & industry standards are graded based on the number, size, location, and type of inclusions found in the diamond, the combination of these 4 result in a diamond being graded as SI1, VS2, or SI2 with slight difference between each grade.

Slightly Included 1, or for short SI1, is a grade defined by GIA as a grade which has inclusions that are noticeable to a skilled grader under 10x magnification.

This leaves a huge room for discussion about whether these (visible to skilled grader) are visible to people with their naked eyes or not.

And this was the root cause of the whole debate around them.

Are SI1 Diamonds Eye Clean?

We always recommend to look for eye clean clarity rather than specifying a particular grade, and to start, SI1 grade is a great point to kick off your search from.

In short:

95% of SI1 diamonds that are less than 1 carat are eye clean.

SI1 clarity grade comes 7th in diamond clarity scale in terms of pureness and absence of any inclusions/blemishes under 10x magnification.

The case for people and without magnification is completely another story, people using their naked eyes will find it extremely hard to detect inclusions (if any) in regular conditions.

This means that when you’re looking at a relatively-small diamond like this stunning 0.7 carat SI1 on James Allen, you will never be able to detect any inclusion by your eye, the 360 HD images here are 20x magnified.

To give weight to each part of the debate here, it’s fair to show both cases for an SI1 diamond.

These two diamonds you see here are identical in terms of general characteristics known as the 4Cs including the clarity(both are SI1):

SI1 Grade Difference

Both diamonds have the same polish & symmetry grades as well, unbelievable, isn’t it?

Well, let’s now take a deeper look (20x or even 40x) at both of them, here is the first one to the left, and this is the one to the right to understand the difference.

To be realistic, images on James Allen are “too revealing” and expose a lot of unseen inclusions, take a look for example on this beautiful 0.9 SI1 diamond on Blue Nile, it’s clear that inclusion are much harder to see when inspecting using naked eye, or standard zoom technologies.

JamesAllen Promo

Where SI1 Stands on GIA Clarity Chart

As we saw already, The SI letters (whether in SI1 or SI2) in clarity grade stands for ‘Slightly Included’; Included refers to the inclusions found on the diamond (under 10x magnification as per GIA definition), regardless of their visibility to naked eye.

GIA defined diamond clarity into 6 groups containing 11 different grades, can be visually represented like this:


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

SI1 has 6 grades above it to the finest/cleanest grade, and 4 grades to the “dirtiest” clarity grade possible, that you probably won’t only see its inclusions, but probably touch them!

You might think that since SI1 is too far from flawless grade and even internally flawless, it will be more to the low end of clarity scale, but that’s not practically the case, for the main reason that the top 2 clarity grades (FL-IF) are extremely high and rare, less than 1% of global diamonds make it to these 2 grades.

You may also like:  Flawless Diamonds - FL: Why you Should NOT Get One?

These 2 grades don’t have any inclusions, pure as water, and for a reasonable comparison, we can take them out of the scale to see where SI1 stands.

This leaves us with 9 grades, and SI1 sits exactly in the middle! 4 grades higher, and 4 grades lower, which makes a bit more sense

827X827 THLD23

SI1 vs Adjacent Grades: VS2 & SI2

If you set your mind on a 100% eye clean diamond, then you can safely get a VS2 (unless you’re buying 3+ carat diamond), but, if you don’t care about having visible inclusions (we doubt that), then SI2 will be the cleanest grade WITH visible inclusions.

In the middle, the SI1 exists.


Let’s start with the easy one:

SI1 vs SI2

The main difference between both grades is that SI2 has inclusions that are very likely to be visible to naked eye, and these inclusions will probably have effect on diamond brilliance and durability.

While for SI1, it’s the opposite, inclusions are most like to be not visible to naked eye, and even when visible, they will have less effect on brilliance & durability.

For a visual comparison, it won’t be fair since both grades might have eye clean & non eye clean diamonds, for a general view, you can browse on sites that offer super imaging technologies like Whiteflash and James Allen.

Whiteflash 360 HD Diamond Videos 970x250 1

SI1 vs VS2

If we look at the GIA definition for VS (1 & 2) grades, we see:

“Inclusions are minor and range from difficult to somewhat easy for a skilled grader to see under 10x magnification”

While for SI (1 & 2) they say:

” Inclusions are noticeable to a skilled grader under 10x magnification”

Since each group contains 2 grades, it’s safe to conclude that VS2 has inclusions that are “somewhat easy” to be seen, and SI1 are noticeable (to some extent) under 10x magnification for a skilled grader.

In plain English, for diamonds around 1 carat and less, SI1 is 95% eye clean, and VS2 is 100% clean.

How to Find a Eye Clean SI1 Diamond?

The 1 million dollar question:

How I can be sure that a particular SI1 diamond is eye clean?

  1. Always look for a magnified image and a certificate. If you’re at a local store, don’t just look at the 50 cm-away diamond from your eye to determine cleanness, try and look closer, even ask for a loupe to better inspect.
  2. Now if you see any inclusion with your eyes, no matter how small it is, look for the next diamond right away!
  3. If you’re unable to see 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
  4. After you see inclusions’ locations on the certificate, try to find them with your own eye physically on the diamond itself, if you can’t, then that’s a good sign.
  5. 99% you’re looking at an eye clean SI1 diamond (and that’s why we always recommend GIA certificates as a first choice).

However, 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).

With these high-definition zooming features, you’ll be able to see what’s not visible to naked eye! In 90% of cases, you will be able to see most inclusions on the diamond, but remember that you’re inspecting a magnified image.

Take a look at this diamond for example, it’s an SI1, looking good actually, but it has some inclusions that are easily seen under magnification, but do you think you can spot them with your naked eye? We doubt.

That’s why you should always get your diamond from a reputable store that gives you high quality images for the diamond.

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

Best Places to Buy SI1 Diamonds?

While a lot of people prefer to see and inspect the diamonds live in the store, we still suggest the online approach!

Online diamond shopping also allows you to filter the exact specifications, in most online vendors, you can easily filter based on 4Cs, polish, symmetry, even table & depth symmetry, and the list goes on.

And when a site has hundreds of thousands of diamonds, even with such amount of filters, you will end up with decent amount of options (probably hundreds) to browse from.

1. James Allen

JA offers a wide selection of diamonds with high-quality images and 360-degree videos to help you evaluate the diamonds.

As of writing, they have more than 39k round SI1 diamonds, all come with 20x & 40x magnified HD videos.

JamesAllen Promo

2. Whiteflash

When you’re getting an SI1, you have to be careful picking an eye clean one, here comes a good choice of dealing with a diamond retailor who are well-known for their premium diamonds.

You might be paying a little extra, but with Whiteflash, you guarantee an unmatched sparkle & premium cut for your diamond.

Read: The Superior Quality Diamonds Store Whiteflash Detailed Review!

Whiteflash 360 HD Diamond Videos 970x250 1

3. Brilliant Earth

Currently, Brilliant Earth has 17000 internally flawless diamonds.

4. Blue Nile

The most popular & well-known online retailer that offers a large selection of diamonds and provides in-depth diamond education to help you make an informed decision.

They currently have 50k round SI1 diamonds, 35k of them have 360 degree images, make sure you only buy a diamond that you can see & inspect.

Blue Nile Ring 2

Tips When Getting SI1 Clarity Diamond

  1. 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 carbon spots, clouds, feathers and pinpoints, etc.
  2. Some inclusions are completely okay to be in the diamond, but there are certain types that you MUST avoid if present.
  3. All diamond clarity grades except the FL class contain these blemishes in various ratios. The more clustered the inclusions on the gemstone, the more conspicuous and apparent it becomes.
  4. The inclusions in the SI1 diamond would -reasonably- become less visible if the inclusions are not gathered up all in one spot or close to the diamond’s table facet of the sample.
  5. Always get a diamond that is graded/certified by reputed organization, namely: Gemological Institute of America (GIA) or the American Gem Society (AGS)ز
  6. If you discover that the inclusions on an SI1 diamond are found just beneath the diamond table region, then you probably need to find another stone to buy!
    Let’s look at an example, this diamond you see here:
    SI1 eye clean with crystal
    Eye clean? Yes.

    Do we recommend it? No of course! Although the minor inclusions on the table & facets won’t hurt, but if you look at 7 o’clock, you will see a deadly black carbon inclusion! And it’s one the worst inclusions you want to avoid in your diamond.

When Carat Makes SI1 Inclusions Visible?

For larger carat weights, it may be wise to consider skipping over SI1 and opting for VS2 instead, although this depends on the type and location of inclusions.

For instance, if a diamond has inclusions on its table facet and is 1.1-1.2 carats or larger, it’s recommended to avoid SI1 and choose VS2 for a safer bet.

This is because larger diamonds make it easier to spot blemishes, as explained in our Diamond Carat Chart Guide: How Weight Affects Size.

In most cases, moving up to VS2 should ensure an eye-clean diamond. However, this may not be enough for very large diamonds (over 3 carats), in which case a higher clarity grade, such as VS1, may be necessary.

Beware of retailers who may try to convince you to prioritize higher clarity grades over carat weight – it should be the other way around.

Bottom Line: Is SI1 Clarity Good Enough?

Always seek the cheapest eye clean diamond clarity and don’t go crazy beyond that.

Vast majority of SI1 diamonds are eye clean, however, it’s important to ensure that there are no imperfections beneath the diamond’s table facet.

If you plan to purchase a larger diamond, such as one over 1.2 carats, some inclusions may be visible even with an SI1 clarity grade, depending on their location and type.

If you have a good budget and are wondering if you should invest more in clarity, it’s recommended to prioritize the cut of the diamond since it’s the most important factor.

Color is also important, but high grades such as D and E are overpriced, and even an F grade may not be worth the extra money. Once you have considered these factors, then you can focus on achieving a higher clarity level.


Still not sure where to buy your diamond?

We always recommend shopping diamonds online and created a Full guide to shop diamonds like a Pro.

Among online retailers, here are our favorite stores (click their logo to visit store):

1) James Allen: Our favorite online store, best diamond imaging technology available today, comes with the largest collection with more than half a million loose diamonds.

Latest JA Logo2) Blue Nile: Widest collection of loose diamonds of all sizes, great imaging technology for most of their  inventory (hundreds of thousands of diamonds), great customer support.

Blue Nile Latest Logo

3) Whiteflash: Home Of A CUT ABOVE® Super Ideal Diamonds, they stand out from the crowd by offering premium diamonds cuts, tailored to those who love the details, at great prices too.

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About the Author

Sophia Martinez

Sophia Martinez is a talented writer with a deep passion for diamonds and an inherent appreciation for their elegance and beauty. Through her evocative and informative writing, Sophia brings the world of diamonds to life, captivating readers with her expertise and creativity.

Driven by a lifelong fascination with gemstones, Sophia has dedicated herself to studying the intricate details of diamonds. Her extensive research and firsthand experiences in the industry have given her a wealth of knowledge in diamond history, trends, and the art of jewelry design.

Sophia's ability to convey the allure and symbolism of diamonds through her words has made her a sought-after writer in the field. Her articles offer insights into the world of diamonds, from the emotional significance of engagement rings to the craftsmanship behind each exquisite piece.

With her talent for storytelling and her deep appreciation for diamonds, Sophia Martinez continues to inspire and educate readers through her captivating writing.