VS vs SI Diamonds: Which Clarity is Better for You?

The incredible transparency of diamonds is one of the reasons they are so brilliant and beautiful. But every diamond, even flawless gems, have a landscape of microscopic features inside them, as unique as a fingerprint. Whether they are mined from the Earth or grown in a laboratory, diamonds with exceptional clarity cost more than diamonds that have visible inclusions inside.

You probably are familiar with clarity as one of the famous 4Cs of diamond quality. Diamond grading labs give diamonds one of six basic clarity grades, subdivided into eleven steps ranging from flawless (F) to very, very slightly included (VVS), very slightly included (VS), slightly included (SI), and Included (I). The two most popular clarity grades for fine diamond jewelry, like diamond engagement rings, are VS, or very slightly included, and SI, or slightly included. These two clarity levels are subdivided into four grades: VS1, VS2, SI1, and SI2. These clarity grades are the most common for nice diamonds, the kind of gems you’ll find in engagement rings at a fine jeweler.

Of course you want nice diamonds! But should you choose VS diamonds or SI diamonds? To understand what these grades really mean, let’s start with a basic explanation of clarity grading, how the grades are defined, and how these grades are applied to different diamonds.

In a gem lab, both mined and lab-grown diamonds are clarity graded to the same standards under 10x magnification. Graders look at the number, size, color and position of inclusions in diamonds. Graders do this all day every day and they are good at spotting the tiny crystals and spots and feathers inside diamonds. The maps of these clarity characteristics are used to tabulate the clarity grade. VS diamonds have fewer inclusions than SI diamonds and so cost more than SI diamonds. Both VS diamonds and SI diamonds are categorized as “eye clean,” with no easily seen inclusions face up without magnification.

Is the difference in price worth it? Which clarity grade represents the best balance of quality and value? Some say that a VS diamond is the best choice. Others say an SI diamond is a better choice. Which you should choose depends both on you, your diamond, and your jewelry piece. We’re here to help you figure out whether a VS diamond or an SI diamond is right for you.

VS Diamonds: Lab Grown and Mined

VS diamonds are totally gorgeous with notable clarity. When you look at a VS diamond, even close up, you won’t see any inclusions with the naked eye. That’s because diamonds that are graded have inclusions that are only visible under magnification. VS diamonds have minor inclusions that are difficult to somewhat easy to see for a skilled grader using 10x magnification. Even under 10x magnification a VS1 diamond may appear flawless to someone who’s not an expert. Generally, VS2 diamonds will have many tiny inclusions or one or two larger inclusions. But you still won’t see the inclusions in a VS2 diamond with the naked eye. That means you definitely won’t see them when your VS diamond is set into jewelry.

SI Diamonds: Lab Grown and Mined

SI clarity diamonds have noticeable inclusions that are easy for a skilled diamond grader to see using 10x magnification. In theory, none of the inclusions in SI diamonds should be visible with the unaided eye. But, in practice, you will probably see the inclusions in SI diamonds if you look closely. Some SI2 diamonds may have inclusions in the center and black spots that are more prominent.

That’s especially true for fancy shapes. The diamond clarity grading scale isn’t different for different fancy shapes but the cuts of some shapes can make inclusions easier to see. Round brilliant diamonds have a dense pattern of triangular reflections that make it more difficult to see inclusions from the diamond’s face up position. But step-cut style fancy shapes like emerald cut diamonds and Asscher cut diamonds have long and large facets that are designed to reflect each other, a beautiful optical effect called the “hall of mirrors” that makes these cuts so stunning. But what that means is that one tiny inclusion, if positioned in the right place, can be reflected over and over again inside the stone.

During clarity grading, the size of the inclusions is judged in proportion to the size of the diamond. That means that larger diamonds have larger inclusions than smaller diamonds with the same clarity grade. The inclusions in a SI diamond two carats or larger will be easier to see than the inclusions in smaller diamonds with the same clarity grade.

Clarity in Lab Grown Diamonds

Just like all of the 4Cs of diamond quality, clarity is graded exactly the same way in lab grown diamonds as in mined diamonds by the same labs and graders. Because inclusions are captured in diamonds as they grow, either deep in the Earth or in a crucible in the laboratory, inclusions in mined and lab-grown diamonds can be different. For example, inclusions such as knots, twinning wisps, diamond crystals, other minerals, naturals, and indented naturals are common in natural diamonds.

Diamonds grown by the CVD method often contain graphite or other mineral inclusions that are a result of the gas environment in which they grow. Diamonds grown by the HPHT method are grown in liquid metal that can sometimes be trapped in the growing crystal forming metal inclusions. In reflected light these inclusions appear white, gray, or black with a metallic luster. One interesting fact is that depending on the size of such inclusion and its location, the stone could possibly be picked up with a magnet when there is a presence of iron.

Lab grown diamonds are the rearrest and purest type of diamonds: Type IIa, which is almost pure carbon. They don’t contain the nitrogen impurities that are the cause of the yellow colors of most natural diamonds which are Type Ia. As growers are working to perfect the process, they are creating lab diamonds with fewer inclusions. It’s easier to find lab grown diamonds with exceptional clarity and fine color and the premium for the best quality is lower than it is for mined diamonds. That means upgrading the quality of your diamond is easier: you can have the beautiful diamond of your dreams for less.

Which Should You Choose?

Choose VS diamonds, lab grown or mined, if:

• You are the kind of person who stores shoes and handbags in felt bags or boxes to make sure they stay pristine
• You want to make sure that your engagement ring is premium quality to symbolize your forever love
• Your diamond is an emerald cut or other step cut
• Your diamond is two carats or more in size
• You love quality above all

Choose SI diamonds, lab grown or mined, if:

• You’d prefer a larger diamond for the same budget
• You’re shopping for earrings or a necklace that won’t be viewed close up
• Your diamond is a round brilliant or princess cut
• Your diamond is less than two carats in size
• You’re looking for value for your money