SI1 Diamond Clarity: Always Seek an Eye Clean First

SI1 Diamonds Clarity - The Full Guide - SI1 Diamond Clarity - Always Seek an Eye Clean First

SI1 diamond clarity is perhaps the most disputed grade in the industry, mainly due to a lack of consensus on whether it’s entirely eye clean or not.

Those arguing that SI1 is indeed eye clean may be closer to the truth as this is essentially what sets SI1 apart from SI2.

For a visual comparison, consider these two SI1 diamonds. On the left is a clear, eye-clean SI1 from James Allen, while the diamond on the right, also graded as an excellent cut SI1, harbors noticeable inclusions that may be visible to the naked eye.

SI1 eye clean and eye-visible

Given such discrepancies, it’s easy to understand the ongoing debate. Therefore, it’s crucial to delve deeper into the nature of SI1 clarity grade diamonds, their price points, how to find one, and the best places to source an exceptional SI1 diamond.

What are SI1 Diamonds?

Diamonds, formed under high pressure and temperature deep within the Earth’s mantle, often trap impurities and irregularities within their crystal lattice structure during their formation. These result in inclusions or imperfections.

These imperfections can impact a diamond’s clarity and value, but they can also render each diamond unique, adding to its overall character.

Pro Tip: Generally, the term “inclusion” refers to any imperfection on a diamond. However, there is a key difference between inclusions and blemishes. Inclusions are internal “birthmarks” that don’t reach the diamond’s surface, while blemishes are external birthmarks visible on the diamond’s surface.

The Gemological Institute of America (GIA), the leading grading lab in the diamond industry, has developed a clarity grading chart. This chart classifies diamonds into six categories and eleven grades based on the visibility of inclusions in a diamond.

827x827 BF CM 2023

Official and industry standards grade SI1 diamonds based on the number, size, location, and type of inclusions present in the diamond. The interplay of these four factors can result in a diamond being graded as SI1, VS2, or SI2, with only slight differences between each grade.

The Slightly Included 1, or SI1, grade is defined by the GIA as a diamond with inclusions noticeable to a skilled grader under 10x magnification.

This leaves plenty of room for debate about whether these inclusions, visible to a skilled grader, are also visible to the unaided eye. It’s this question that has sparked the ongoing discussions around SI1 diamonds.

Are SI1 Diamonds Eye Clean?

When it comes to diamond shopping, we typically advise focusing on finding diamonds that are “eye clean” instead of focusing solely on a particular clarity grade. SI1 is an excellent clarity grade to begin your search with.

In short:

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

SI1 clarity grade ranks seventh on the diamond clarity scale in terms of purity and the absence of inclusions or blemishes under 10x magnification.

The story differs when examining diamonds without magnification. Most people, relying solely on their naked eyes, would find it exceedingly challenging to detect inclusions (if any) under ordinary conditions.

For instance, in a smaller diamond such as this beautiful 0.7 carat SI1 from James Allen, you would not detect any inclusions with your naked eye. The 360 HD images you see here are magnified 20x.

In all fairness to the ongoing debate, we should illustrate both sides of the SI1 diamond argument.

Take these two diamonds as an example. They are identical in terms of the universally accepted 4Cs, which include clarity (both are SI1). They even share the same polish and symmetry grades—surprising, right?

SI1 Grade Difference

Now, let’s zoom in (20x or even 40x) on each of them. Here is the first one on the left, and the second one on the right. This will give you an understanding of the difference.

Realistically speaking, the images on James Allen tend to be “too revealing,” exposing a lot of otherwise unseen inclusions.

For instance, take a look at this lovely 0.9 carat SI1 diamond on Blue Nile. It’s clear that inclusions are much harder to see when inspecting the diamond with the naked eye or standard zoom technologies.

JamesAllen Promo

Where SI1 Stands on GIA Clarity Chart

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

The GIA categorizes diamond clarity into six groups containing 11 different grades, as depicted in this visual representation:


Pro Tip: The SI3 level isn’t recognized by major certification labs like the GIA. It was introduced by EGL primarily for the benefit of sellers, not buyers.

SI1 has six grades above it leading to the purest, cleanest grade, and four grades below it leading to the lowest clarity grade where you can not only see the inclusions but possibly feel them!

You might assume that since SI1 is far from the flawless grade and even internally flawless, it would be closer to the lower end of the clarity scale. However, this isn’t practically the case. The top two clarity grades (FL-IF) are extremely high, rare, and represent less than 1% of global diamonds.

These two grades have no inclusions and are as pure as water. For a reasonable comparison, we can exclude them from the scale to see where SI1 stands.

Doing so leaves us with nine grades, with SI1 sitting right in the middle! Four grades are higher, and four grades are lower, which makes a lot more sense.

SI1 vs Adjacent Grades: VS2 & SI2

If you’re determined to acquire a diamond that is 100% eye-clean, you can confidently opt for a VS2 grade (unless you’re buying a diamond of 3+ carats). Conversely, if visible inclusions aren’t a concern for you (which seems unlikely), an SI2 grade would be the cleanest option with visible inclusions.

The SI1 grade sits somewhere in between these two.


Let’s begin with an easy comparison:

SI1 vs SI2

The primary distinction between these two grades is that an SI2 diamond’s inclusions are likely to be visible to the naked eye. These inclusions could potentially impact the diamond’s brilliance and durability. Conversely, in an SI1 diamond, inclusions are likely not visible to the naked eye, and even if they are, they’ll have less impact on the diamond’s brilliance and durability.

For a visual comparison, it wouldn’t be entirely fair since both grades could potentially house eye-clean and non-eye-clean diamonds. For a general idea, you can browse on platforms offering advanced imaging technologies like Whiteflash and James Allen.

Whiteflash 360 HD Diamond Videos 970x250 1

SI1 vs VS2

Looking at the GIA definition for VS (1 & 2) grades, it reads:

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

For SI (1 & 2), it states:

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

Given that each group contains two grades, it’s safe to conclude that VS2 has inclusions that are “somewhat easy” to spot, and SI1 inclusions are noticeable (to some degree) under 10x magnification for a skilled grader.

Simply put, for diamonds approximately 1 carat or less, SI1 is 95% eye-clean, and VS2 is 100% clean.

How to Find a Eye Clean SI1 Diamond?

The million-dollar question is:

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

  1. Always inspect a magnified image and a diamond certificate. If you’re in a physical store, don’t merely rely on a glance at the diamond from 50 cm away to determine cleanliness—look closer and even ask for a loupe for better inspection.
  2. If you see any inclusion (with your own eyes), regardless of how small it is, move on to the next diamond immediately! If you can’t spot any inclusions, check the diamond’s certificate. On GIA certificates (for diamonds 1+ carats), you’ll see a clarity section:
    GIA Clarity section for VVS2 diamond
  3. After spotting the inclusions’ locations on the certificate, try to find them with your own eyes on the diamond. If you can’t, then that’s a positive sign. In 99% of cases, you’re looking at an eye-clean SI1 diamond (which is why we always recommend GIA certificates as a first choice).
  4. However, if you’re shopping on an online store like James Allen or Whiteflash, you’re covered. These sites provide 360-HD images of diamonds, allowing you to rotate the image and zoom in 20x (and on James Allen, you can even zoom in 40x with Superzoom technology).

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

Consider this diamond, for example. It’s an SI1 grade, which looks pretty good, but it has some inclusions that are easily seen under magnification. Do you think you could spot them with your naked eye? We doubt it.

This is why you should always purchase your diamond from a reputable store that provides high-quality images of the diamond.

This way, you can be 100% confident that you’re getting an eye-clean SI1 diamond, and that you’ve received the best value for your money! You won’t have to spend more on something you won’t even be able to discern.

Best Places to Buy SI1 Diamonds?

While many people prefer to see and inspect diamonds in-store, we still recommend the online approach. Online diamond shopping lets you filter by precise specifications. Most online vendors allow easy filtering based on the 4Cs, polish, symmetry, table & depth percentages, among others.

Even with numerous filters, the vast inventories of these websites will still leave you with plenty of options to choose from.

1. James Allen

James Allen offers a broad selection of diamonds with high-quality images and 360-degree videos to assist in your diamond evaluation.

At the time of writing, they have more than 39,000 round SI1 diamonds, all complete with 20x & 40x magnified HD videos.

JamesAllen Promo

2. Whiteflash

When purchasing an SI1 diamond, careful selection of an eye-clean stone is critical. Here, Whiteflash is a good choice.

Known for their premium diamonds, you might pay a little extra with Whiteflash, but you’re guaranteed unmatched sparkle and premium cut for your diamond.

Whiteflash 360 HD Diamond Videos 970x250 1

3. Brilliant Earth

Brilliant Earth is well-known for their lab-grown diamonds, but they also have an extensive inventory of natural diamonds, making them a major player in diamond sourcing and large-scale inventory.

Currently, Brilliant Earth has 17,000 SI1 diamonds.

4. Blue Nile

Blue Nile, the most popular and well-known online retailer, offers a large selection of diamonds and provides in-depth diamond education to help you make an informed decision.

They currently have 35,000 round SI1 diamonds, 28,000 of which come with 360-degree images. Make sure you only purchase a diamond you can see and inspect.

Blue Nile Ring 2

Tips When Getting SI1 Clarity Diamond

  1. When buying an SI1 clarity diamond, another factor to consider is the dispersion ratio of the inclusions. SI1 diamonds typically contain carbon spots, clouds, feathers, pinpoints, etc., or a combination of these.
  2. Some inclusions are completely fine to have in the diamond, but there are certain types you MUST avoid if present.
  3. All diamond clarity grades, except the flawless (FL) class, contain these blemishes in varying ratios. The more clustered the inclusions on the gemstone, the more conspicuous and apparent they become.
  4. The inclusions in an SI1 diamond will reasonably become less visible if they are not all gathered in one spot or close to the diamond’s table facet.
  5. Always purchase a diamond that is graded or certified by a reputable organization, namely: Gemological Institute of America (GIA) or the American Gem Society (AGS).
  6. If you find that the inclusions in an SI1 diamond are located just below the diamond table region, you probably need to find another stone!
    Let’s consider an example. This diamond you see here:
    SI1 eye clean with crystalEye clean?
    Do we recommend it?
    No, of course not! Although the minor inclusions on the table and facets won’t hurt, if you look at the 7 o’clock position, you will see a deadly black carbon inclusion! And it’s one of the worst inclusions you’d want to avoid in your diamond.

When Carat Makes SI1 Inclusions Visible?

As a diamond’s carat weight increases, inclusions can become more visible due to the larger surface area. For larger diamonds, especially those over 1.2 carats, you might want to consider choosing a clarity grade of VS2 or higher to ensure the diamond appears eye-clean.

This is particularly relevant if the diamond has inclusions on its table facet – the flat surface on the top of the diamond that faces upwards when set in jewelry.

In diamonds larger than 3 carats, you might need to opt for even higher clarity grades like VS1 to ensure the diamond is eye-clean. Larger diamonds simply make it easier for the eye to spot inclusions and blemishes. However, always remember to prioritize cut and carat weight over clarity, as these have a more significant impact on a diamond’s appearance.

Bottom Line: Is SI1 Clarity Good Enough?

For many people, an SI1 clarity diamond is a great choice. It provides a balance between cost and visual appeal, as the vast majority of SI1 diamonds appear eye-clean, meaning their inclusions aren’t visible to the naked eye.

However, there’s a caveat. If you’re looking at larger diamonds, above 1.2 carats, inclusions in an SI1 clarity diamond may become visible, depending on their type and location. In such a case, it’s advisable to opt for a higher clarity grade.

If you have a decent budget and are considering investing more in clarity, remember to prioritize cut first – it significantly impacts a diamond’s brilliance and sparkle. Color is also important, but very high color grades (like D or E) can be overpriced, and even an F color might not be worth the extra cost for most people.

Once you have considered these aspects, then you can think about getting a higher clarity grade. But in general, always strive to find the cheapest eye-clean diamond – you don’t need to pay for clarity that you can’t see.

Remember, the goal is to find a beautiful diamond, not one that just sounds good on paper.

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 Logo

  2. 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.

    WF logo black

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