SI Diamond – Know This Before Buying One

si diamond​About half of all-round cut diamonds available on the market today have clarity grades of slightly included (SI) or included (I). As the name of the diamond grade implies, SI diamonds have inclusions and blemishes that you can see under magnification.

Using a 10x magnifying loupe, you can easily spot the inclusions in SI diamonds, even though they typically look flawless when seen by the naked eye. This is why SI1 graded diamonds are in such demand for shoppers on a budget. People can get a larger diamond without compromising on cut quality.

What is important to know is that two GIA-graded (gemological institute of America) SI1 diamonds can actually look very different when you compare them in person.

Some SI1 loose diamonds will appear completely eye clean, while others have inclusions that can be spotted instantly. The location, color, and size of the flaws are what determines how easily they can be seen when the stone is face up. There is no way you can tell from the grading report if a diamond is or is not eye-clean. You would need to view HD videos and images of the diamond, which you can get when shopping for engagement rings online at James Allen. We’ll discuss this in more detail further on in the blog.

What is an SI diamond?

Diamond Clarity Scale VVS2 DIamondThe letters SI stand for “small inclusions” or “slightly included diamonds” which means that an SI diamond has inclusions that can be seen under 10x magnification. In some stones, they can also be seen by the naked eye. This is especially true of larger diamonds or if the inclusions are in the center with no facets to conceal them.

The SI clarity range includes slightly included 1 (SI1) and slightly included 2 (SI2). SI1 diamonds have smaller, fewer and less visible inclusions and flaws than SI2 diamonds. These are small- to medium-sized inclusions that could be located anywhere in the diamond but are more likely to be in the center. The number of inclusions in SI1 and SI2 diamonds can vary. There could be one or several different flaws. But usually, there is a single grade-setting inclusion instead of a lot of small ones.

Feather Diamond Inclusion

Crystal Inclusion Diamond

Inclusion CloudThe type of inclusions you’ll typically find in SI1 and SI2 diamonds are black or white crystals, cavities, chips, clouds, feathers, indented naturals, knots, needles and twinning wisps. Since SI1 diamonds belong to a higher clarity grade they are more expensive than SI2 diamonds. SI2 diamond son the other hand are a lot more affordable. Less than half of the gem-quality diamonds in the world fall within the SI clarity range. You can often get a beautiful eye clean SI diamond for a reasonable price of 10% to 20% less than what you would pay for a VS diamond. This is what’s driving the demand for SI diamonds.

Comparison of SI1 vs. SI2 Diamonds

Diamonds with clarity grades of SI1 and SI2 have inclusions and these may or may not be visible with the naked eye. They are of varying sizes and can be found in the center and/or on the sides along the girdle. The main differences between the two clarity grades are the type of inclusions as well as the amount. Learn more about SI1 vs. SI2 clarity grade diamonds here.

Is an SI1 diamond considered good?

Yes, definitely! An SI1 diamond may not be flawless, but it will look beautiful and hold its value. It is very unlikely that anyone would look closely enough to spot any inclusions. Like most high-quality diamonds, you can expect both SI1 and SI2 diamonds to increase in value over time. To safeguard this, we recommend that SI diamonds be carefully set by reputable gemologists only.

Why SI Diamonds Enjoy Such Popularity

The reason SI diamonds are so popular is because those in the know can get exceptional value for the money. If you are well informed and know what you’re looking for, you can get a great buy. Look for an SI diamond with no visible inclusions as you peer through the crown with the naked eye. In other words, you want an eye-clean diamond. The best value is in eye-clean SI and VS diamonds. These diamonds cost far less than diamonds with clarity grades of Internally Flawless (IF) or Flawless.

I do not recommend that you settle for a diamond below an SI clarity grade, especially if you are looking at larger stones. The reason is because the inclusions and flaws are larger and more noticeable. The inclusions in smaller SI diamonds of less than 0.50 carats cannot be seen with the naked eye.

How to Buy a SI1 Clarity Grade Diamonds

Diamond Comparison ToolThe secret to buying the best looking SI1 diamonds is to only choose diamonds with widely dispersed inclusions. I would avoid diamonds with inclusions that spread into the body of the stone or that have inclusions near the center.

It is vitally important to NEVER buy an SI diamond without seeing it first. If you’re shopping online and the vendor doesn’t have HD videos or images that allow you to closely inspect the diamond, find someone who does.

Just follow the rule: No images or videos, no shopping. The last thing you want is to blindly buy an ugly diamond that will remind you every day how you squandered your opportunity.

If you have your heart set on an SI1 diamond, your best bet would be to rely on James Allen or Blue Nile. You will be provided with magnified images and videos of each stone you’re interested in, so you can’t go wrong. James Allen enjoys the confidence of consumers from all walks of life, with widely varying budgets.

What’s more, they will have one of their in-house gemologists physically inspect the stones you’re considering upon your request. And this would be for free. What they do is request their suppliers to send them the diamonds on your shortlist. They will then personally check the clarity as well as the stone’s optical performance. You will be provided with a report summarizing their findings, which will further assist you in making your decision.

Helpful Tip

When viewing the James Allen diamonds, turn down the magnification from 20x to just 2x, as seen below:

This allows you to see the diamond as it appears in person. While it’s still at 2x magnification, we believe this is an accurate image since you’ll be viewing it through your computer screen. Furthermore, any James Allen diamond that looks eye clean under 2x magnification will very likely look eye clean in person!


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