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What is SI1 Diamond Clarity and Should I Buy It?

si1 clarity diamond engagement ring

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When it comes to engagement rings, it’s hard to go past diamonds. Finding the right one, however, can prove to be a challenge. There are many technical characteristics (and jargon) that affect a diamond’s look and price but the common are the 4C’s of cut, color, carat and clarity.

We take a look at how understanding the clarity scale, particularly the lower SI1 grading can potentially get you the diamond of your dreams at a fraction of the price.

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Here’s a closer look at SI1 diamonds, whether they’re the right choice and what other diamond shoppers say.

Is Diamond Clarity Important?

si1 clarity diamond

SI1 emerald cut diamond. Check price here.

Diamonds are formed over millions of years deep within the earth where pressure and heat turn compressed carbon into diamonds. This process will naturally result in some imperfections – and because perfection is almost impossible in nature, almost every diamond has them.

The degree to which defects are present is called diamond clarity. Some flaws are visible and others can only be seen with a jewelers’ loupe (magnifying glass) or microscope, but clarity is important because flaws interfere with the way light passes through a diamond, which can affect how brilliant and shiny it is.

There are also two types of flaws that affect clarity – these are ‘inclusions’ and ‘blemishes’. When a diamond is described as ‘included’, it means that there are imperfections on the inside of the stone. If a diamond has ‘blemishes’ it means that there are marks on the outside.

More blemishes and inclusions will generally result in a duller diamond, but higher clarity also increases a diamond’s value.

And we’re not just talking a few extra dollars.

Differences in clarity grading can increase the cost of a diamond by hundreds of dollars. This is why it pays to know a little about clarity so that you can decide what happy medium you are willing to pay for.

How Is Clarity Measured? 

si1 round diamond closeup

SI1 round cut diamond. Check price here.

The most commonly referenced scale is set by the Gemological Institute of America (GIA). The GIA ranks clarity from best to worst on this scale:

  • Flawless (FL)
  • Internally Flawless (IF)
  • Very Very Small Inclusions 1 (VVS1)
  • Very Very Small Inclusions 2 (VVS2)
  • Very Small Inclusions 1 (VS1)
  • Very Small Inclusions 2 (VS2)
  • Small Inclusions 1 (SI1)
  • Small Inclusions 2 (SI2)
  • Inclusions 1 (I1)
  • Inclusions 2 (I2)

Eye-clean is the “unofficial” marker on the clarity scale that is used to describe a diamond with imperfections that are only visible with the naked eye. Although SI1 diamonds are on the lower end of the clarity scale, they are only slightly included to the 1st degree. This means that most of the imperfections can only be seen with a jeweler’s loupe at 10x magnification.

Are SI1 diamonds really eye-clean?

This reddit user thinks so:

“GIA clarity grade is generally very strict. Unless the stone has one large black crystal on the table, it is safe to assume in the one carat range that a SI1 would be eye clean.”

SI1 diamond ring

SI1 diamond ring by Prime Settings. Can you notice any inclusions? We don’t think so.

Check Price Here

But a safe assumption probably isn’t enough for one of the most important purchases in your life. So, let’s try and understand a little bit more about how to spot imperfections and how to hide them. 

How to Shop for SI1 Diamonds

According to one reddit user:

“I bought an SI1 diamond ring and I couldn’t be happier. We saved a ton of money and you can’t see any inclusions. If the inclusions are only visible from the bottom of the diamond or if they are off to the side of the diamond on top so that they don’t show through the flat table, then they are typically going to be eye clean.”

Although most SI1 diamonds will be eye-clean, there is still the risk of getting an SI1 diamond with fewer marks that are more visible. And unfortunately, if you’re buying blind, lab reports for smaller diamonds (typically under 1 carat) will not indicate where, if any, inclusions are located.

GIA clarity plot

GIA Clarity Plot

However, for larger diamonds, the GIA provides a clarity plot. It’s important to understand how to interpret clarity plots.

A clarity plot is basically a map that shows you what imperfections are present and where on the diamond they are. The easiest and most obvious thing to look for with an SI1 clarity plot is the lack of inclusions. Remember, an SI1 grade means that the diamond is flawed, so if the map is empty that is a red flag. This usually means that there is a hidden flaw (usually a cloud) that isn’t shown, and this should be mentioned in the comments.

It’s also worth noting that a clarity plot won’t show you the actual appearance of the diamond. So even if the clarity plot only shows one or two markings, the low SI1 rating means that the markings could be severe and affect the look of the diamond. Similarly, a clustered clarity plot does not always mean a visibly flawed diamond. Sometimes there are many small imperfections mapped on a plot, but none of them can be seen with the naked eye.

According to one reddit user:

“I was lucky to find an SI1 diamond that didn’t have any marks on it, and I did this online! My only advice is – You need to request a picture of the diamond to make sure it’s not cheaper for a reason. You’ll mainly want to check that it doesn’t have a hazy or milky appearance or ugly inclusions in visible places.”

This is why the most important factor when buying a diamond is to view the actual diamond itself, either in person or via high-quality HD images and/or videos. We can’t stress enough how important this is.

si diamonds round shape

Take a look at the two diamonds apart. Although they’re very similar in specifications and even in price, there is a notable difference in how they look. The diamond on the right has very clear blemishes on the surface, which detract from its beauty. The diamond on the left,  however, offers better clarity.

Can SI1 Blemishes and Inclusions be Hidden?

halo setting SI1 clarity engagement ring

The right setting can hide flaws in your diamond. See this halo ring here.

According to one reddit user: “SI1 can meet your needs, but you really have to curate to find them IMO.”

We agree. Knowing how to hide imperfections on an SI1 diamond can save you a lot of money. A clarity plot, video and pictures will help you determine whether your SI1 diamond will look dull or damaged. It will also give you an indication of whether the flaws can be hidden.

A trick to buying SI1 diamonds is to find one with inclusions and blemishes that are spread apart or that blend into the diamond. Some imperfections, such as pinpoints or feathers that are spread apart are difficult to see. Some are well lined up with facets and are well-hidden. Others located near the bezel or girdle facets can even be covered up by the prongs of your chosen setting.

Choose a setting that hides visible inclusions. Such settings include bezel, halo or side stone. However, these will only work if the inclusions are not smack bang in the middle of the diamond.

Are S1 Diamonds the Best Value?

si marquise cut engagement ring

SI1 marquise cut diamond ring by Ivy and Rose Vintage. Check price here.

Unless you really want a paper-perfect diamond, then it is more important to pay for clarity that you can see rather than a clarity grade.

This is why SI1 diamonds that are eye-clean often work out to be good value. This also allows you to spend more money on more visible things such as diamond size, cut and setting. So long as you are happy with the way your diamond looks, no one (except for a jeweler with a loupe) will be able to tell the difference between a crystal-clear diamond and the SI1 that you chose.

And the difference in price between a Flawless diamond and an SI1 diamond? Around $6,570!

Are Some Imperfections Worse Than Others?

Not all imperfections are equal – some affect clarity greatly, some can barely be seen and others can compromise durability. The most common naturally occurring imperfections are:

Pinpoints: Pinpoints are common blemishes that look like tiny dots that can be seen on the top facet of a diamond. Pinpoints impact the brilliance of a diamond as the top facet (or table) is the largest facet of a diamond and refracts light that shines out of the diamond. In short, it is the part of the diamond that shines the light we see. A few pinpoints spread out are generally fine, but too many can impact the brilliance of your stone.

Crystal: Crystals are mineral deposits within a diamond. Sometimes smaller diamonds can form within a larger diamond – in this case, the crystal is colorless and doesn’t affect the look too much. Colored deposits of black (carbon residue), reds (garnet minerals) and greens (peridot minerals) are more visible and can impact the way the light reflects and the brightness or whiteness of the light that shines through.

Cloud: A cloud is a generic term used to describe pinpoints or crystals clustered very close together. Sometimes the cloud is difficult to see (for example, if the pinpoints are tiny), but other times the imperfections are so close that they make the diamond appear milky or dull. 

Feathers: Feathers are also common and refer to internal cracks in the diamond. Most feathers are minuscule and can only be seen at particular viewing angles or when the stone is moved and the feather catches the light. But if they run through the entire length of the diamond or reach the surface, they can affect the durability of the diamond which should be avoided.

Graining: Graining refers to faint milky lines within a diamond that forms as a result of irregular crystal growth. Depending on their severity, grains can look like faint lines or streaks, or they can look like obvious creases or reflections.

Cavity: A cavity is a cleft on the diamond’s surface that is usually created when an inclusion gets (accidentally) opened during the polishing stage. Cavities are one of the most visible imperfections as trapped dirt and oil darkens within the cavity and make it more visible. Sometimes a diamond cutter can polish off the cavity, but this will result in a loss of weight in the diamond. Many cutters choose to keep the cavity to preserve the weight of the diamond as this will give them better selling value.

The Bottom Line

An SI1 diamond can offer excellent value without compromising on quality and appearance. The important factor is to comb through the options to find a stone with no visible inclusions. At least, with visible inclusions in hidden parts of the diamond.

This way, you can have your cake and eat it too!

If you’re looking for an SI1 diamond, we recommend starting your search on James Allen. The site is known for their high-quality diamonds, extensive range and excellent customer service and website that makes shopping online for a high-ticket item like a diamond a breeze.