Jewelry Blog

Expert Guide to the SI1 Clarity Diamond

what is SI1 clarity diamond

If you’re looking for a high-quality stone, SI1 clarity diamonds provide a balanced blend of affordability, beauty, and clarity. But without enough information, you might end up with a lackluster diamond. We’ll break down everything you need to know about SI1 clarity diamonds to help you make an informed decision.

What Is SI1 Clarity?

SI1 clarity infographic with round loose diamond

“SI” stands for “Slightly Included,” while “1” means “to the first degree.” So, these diamonds feature inclusions a jeweler’s loupe can uncover at 10x magnification. Inclusions are slight imperfections or blemishes on the stone. With SI1 clarity diamonds, the inclusions are usually invisible to the naked eye. Regardless of their shape, virtually all SI1 stones are eye-clean, a feature that attracts many potential buyers and collectors.

In some cases, the blemishes may be visible even without magnification. Consequently, it’s necessary to carefully inspect each stone that piques your interest. With some SI1 diamonds, you might see inclusions like crystals, feathers, and clouds.

Most experts follow the GIA grading scale. It measures the diamond’s grade, position, and color grade. Additionally, it covers clarity, carat, and cut grades. Along with color, these three parameters comprise the four Cs of diamond grading. Each diamond must undergo a stringent evaluation to receive an accurate grade. A diamond’s grade helps jewelers and customers understand the stone’s true value.

In total, the GIA grading scale has 11 grades. The top category is for FL (Flawless) diamonds, while the bottom is for I (Included) stones, which have imperfections visible at 10x magnification. Depending on the nature of the inclusions, they could impact the opaqueness and shine of the stone.

SI1 Diamond Pricing and Chart

Diamond Clarity Chart featuring eight diamonds of varying clarity with highlighted inclusions

SI1 diamond prices vary based on the type and location of inclusions. So, shoppers should be careful when they find a bargain deal for a stone with a lower clarity rating. The blemishes are likely more prominent if the price is too good to be true.

The inclusions are usually imperceptible with SI1 diamonds, especially round ones. Round shapes look stunning when set in rings and necklaces and are suitable for hiding imperfections. Even though the SI1 stone may feature dark blemishes, they sit in positions on the edge of the diamond. Once the jeweler places the diamond in a ring setting, the prongs will cover the dark spots.

In addition to shape, the size of the diamond plays a significant role in how noticeable its imperfections will appear. For example, a 0.5-carat SI1 stone with several gray blemishes will seem perfect to the naked eye, although you’d spot the flaws with a loupe. If you take a 3-carat SI1 diamond with similar inclusions, you’d be able to point out the blemishes immediately, even without magnification.

The same principle applies to heavier stones. If you want to invest in a 4-, 5-, or 6-carat diamond, expect to find several options with noticeable inclusions. This doesn’t mean you have to say goodbye to stunning 6-carat gems.

The following chart should give customers a good idea of what to expect when shopping for SI1 diamonds. 

0.5-Carat Round Cut G Color$900-$2,000
1-Carat Round Cut G Color$4,000-$5,500
2-Carat Diamond$12,000-$25,000

The Best Shapes for SI1 Diamonds

diamond cuts including round-brilliant, princess, oval, cushion, radiant, pear, emerald, and heart

As we mentioned, the shape of the diamond affects whether it will appear eye-clean.

With SI1 and SI2 gems, you should steer clear of square emerald or Asscher shapes. These step-cut diamonds feature a higher crown, step facets, and a small table that enhances their brilliance.

The cropped corners provide an octagonal shape that, although beautiful, doesn’t do much to hide inclusions.

Fortunately, many other shapes maximize the beauty of SI1 gems without drawing attention to their flaws, including the following.

Round Cut

platinum ring featuring round-cut diamond and baguette cuts on shoulders

Round brilliants are one of the most sought-after stones on the market. They’re perfectly symmetrical gems and the only shape that receives a GIA cut grade. They hide clarity and color imperfections exceptionally well and are a popular choice for engagement rings.

Princess Cut

top-down view of a loose princess cut diamond

This cut resembles an inverted pyramid from the side and features sharp corners. Princess-cut SI1 gems are brilliant and rarely display visible inclusions. Expert jewelers typically advise customers to set princess-cut stones with prints to shield the sharp corners and prevent chipping.

Oval Cut

dazzling platinum ring with oval-cut diamond and detailed embellishments

Oval cuts are another in-demand shape because they make the stone appear larger. The shape creates the illusion that the ring-wearer has slimmer fingers. Although they conceal clarity well, these diamonds sometimes display warmth in J and I colors. Still, they’re an excellent choice for those who appreciate the brilliance and fire of round diamonds but want a unique piece.

Cushion Cut

delicate and charming platinum ring with cushion-cut diamond within floral diamond halo

Cushion cuts have several varieties, and the final choice depends on the customer’s personal preference. They usually have more fire than other shapes, although with less brilliance.

Radiant Cut

Radiant cuts have cut corners, straight edges, and brilliant faceting. SI1 radiant cuts seamlessly hide clarity and color imperfections, making them a great value for the money.

Pear Shape

pear-shaped diamond set in three prongs on delicate band with adorned shoulders

Pear-cut gems are sometimes called teardrops due to their sharp points and rounded ends. Similar to ovals, these stones elongate the fingers and mask flaws well. If you choose a pear shape in a lower color, expect to see some warmth in the sharp tip.

Heart-Shaped Diamonds

Heart-shaped SI1 gems don’t mask inclusions as well as ovals or cushion cuts, but they outperform round shapes. Plus, they’re some of the most visually appealing gems available.

As a rule of thumb, avoid baguettes and emerald-cut stones when shopping for SI1 clarity. If you’ve set your sights on a step-cut, consider going for a VS1 stone to get the best combination of price and brilliance.

Is It a Good Idea to Buy an SI1 Clarity Diamond?

dainty gold ring with round center diamond and tapered baguettes on shoulders

Buying an SI1 clarity diamond is the way to go if you want a stunning, eye-clean gem at a fraction of the price of the FL grade.

Since you’re paying for visible quality and not the official clarity grade, you can invest more in the diamond cut, size, and setting. As long as you’re satisfied with your stone’s look, nobody will be able to tell the difference between your piece and a flawless gem. Well, nobody except for an expert jeweler. But even they would need to use a jeweler’s loupe.

The price differences between SI1 and FL diamonds can exceed $6,000. Thus, you can save money without sacrificing sparkle and brilliance.

However, inexperience can lead to mistakes. Unless you’ve handled diamonds before, you might fall for the initial appeal of a specific shape. You’ll purchase an SI1 emerald cut only to realize later it’s not as perfect as you thought. For this reason, customers should only work with jewelers with a proven track record and years of experience.

Shop SI1 Clarity Diamond Rings

Types of Inclusions in an SI1 Diamond

Several clarity features can appear in SI1 diamonds. While some are minor mineral inclusions, others are flaws on the surface or in the gem’s crystal structure.

Most imperfections in SI1 stones will be cloudy formations, crystal inclusions, or pinpricks. Twinning wisps, feathers, and cracks might also appear. These features can occur in different colors and sizes and significantly impact a diamond’s clarity grade. In terms of grading, small and light-colored flaws are less significant than large and dark spots.

You can notice the impact of inclusions when comparing two similarly cut diamonds. For example, a princess-cut SI1 gem with a light-colored inclusion in the center still looks gorgeous. Also, it’s more visually appealing than an identical stone with a dark blemish in the same position.

Crystal Inclusions

round diamond with crystal Inclusion highlighted by red circle

Crystal inclusions are mineral crystals embedded within the diamond. The diamond contains another diamond in its structure if the crystals are colorless. But the inclusions can come in various colors, from black to red to green. Colored crystals are more noticeable to the naked eye than their colorless counterparts, so you should avoid them when shopping for SI1 diamonds.

Cloudy Formations

round diamond with cloudy formations highlighted by red circle

A cloud inclusion is a term that describes a wide range of crystals or pinpoints grouped closely together. Depending on the type of cloud inclusion, it can degrade the diamond’s appearance.

For instance, clusters of dense clouds may give the gem a hazy appearance and disrupt its light transmission features. But diffused clouds usually won’t negatively affect the gem’s quality.

Pinpoints or pinpricks are small black or white crystals embedded within the diamond. They resemble small dots and are visible with a jeweler’s loupe at 10x magnification.

Twinning Wisps

round diamond with twinning wisps highlighted by red circles

Twinning wisps are a group of clouds, crystals, or pinpricks that develop during the gem’s formation process. The diamond might stop developing during its growth phase due to unsuitable conditions. When it continues growing in a new direction, twinning wisps could occur. Essentially, these inclusions are a combination of different flaws that follow a chaotic pattern.


round diamond with feather Inclusion highlighted by a red circle.

Feather inclusions are small cracks or fractures within the stone. Depending on the angle, some feathers appear transparent and nearly invisible, while others look white when light hits the diamond.

Severe fractures can affect the gem’s durability, especially if they rise to the surface. When inspecting an SI1 stone with feather inclusions, make sure the imperfections aren’t near the girdle. Avoid gems with inclusions that have an unsightly color.

Although some customers may be disappointed to hear the diamond of their choice has inclusions, this isn’t always a deal breaker. After all, nearly all diamonds have some type of inclusion. Many appear while the gem is growing deep within the earth. Thus, the guiding principle for diamond shoppers should be whether the stone is eye-clean.

How Inclusions Influence Grading

jeweler using claw tweezers to examine loose diamond with loupe in the background.

Five factors determine whether a diamond will receive an SI1 clarity grade. These are the inclusions’ nature, size, number, relief, and location.

  1. Size: Size is arguably the most significant aspect of grading clarity. The larger the inclusions, the more they affect the gem’s appearance.
  2. Nature: Nature indicates the type of inclusion. It also measures the inclusion’s depth within the stone. If the inclusion sits on the diamond’s surface and doesn’t reach its internal structure, it’s usually called a blemish.
  3. Location: The location of the inclusion indicates where on the stone it occurs. It will be more visible to the naked eye if it’s closer to the center. Additionally, the diamond’s clarity grade will drop. When the inclusion is closer to the girdle, it’s more challenging to spot. Let’s examine how this factor impacts SI1 diamonds. For example, if you’re deciding between two 1.5-carat diamonds, look at the location of their inclusions. One may have them clustered in the center, making it an undesirable choice. The other could have them to the side, so the imperfections will be hardly noticeable. The less apparent inclusions could impact the price by 5%, making this option a smart investment.
  4. Number: The number of inclusions is another factor that may impact a stone’s clarity and appearance.
  5. Relief: Relief refers to the contrast between the inclusions and the stone. A higher relief level could make the gem appear darker.

Are SI1 Diamonds Eye-Clean?

diamond cluster ring with swirling sunburst halo

Although the clarity grade can point you in the right direction, the most important aspect of diamond shopping is determining whether the gem is eye-clean. SI1 diamonds will be clean in many shapes.

Eye-clean diamonds are free of any imperfections when viewed in normal circumstances. Although your eye can’t spot any flaws, you’ll find them when you use a jeweler’s loupe. When you set it in a ring and wear it on your finger, it will look flawless.

You don’t have to choose a higher clarity grade if you find an eye-clean SI1 diamond that checks all your boxes.

Work with a professional to find a round-cut SI1 gem under 1 carat. As mentioned, eye-clean SI1 stones typically feature an oval, princess, or pear shape.

How to Buy a Loose SI1 Diamond

Jeweler examining a Loose Diamond Under a Loupe.

Loose diamonds are diamonds without a setting. While you can pick out a beautiful ring in a traditional brick-and-mortar store, the setting can make the gem appear more high-quality than it is.

Fortunately, the internet has simplified diamond shopping, introducing customers to more options that meet their criteria.

Here are the benefits of buying loose SI1 diamonds.

Color and Clarity Assessment

Preset diamonds are only partially visible, which complicates assessing their color and quality. You can look at a loose gem from all angles and ensure it has the color and quality you want.

Light Performance and Cut Quality

The best online vendors provide detailed imaging and video that perfectly displays the diamond’s cut quality. You can also use filtering tools to narrow your search and compare two similar stones. You’ll understand how well they’ll fare in day-to-day circumstances and select the option with unmatched light performance.


Online vendors offer customers a treasure trove of options, from high-end stones to budget-friendly gems. You can quickly find a diamond that matches your personal taste and has the qualities you appreciate.


You don’t have to break the bank to purchase a stunning loose diamond. Although the shape, size, and clarity grade influence pricing, you can still buy a gorgeous stone without straining your budget.

Professional Assistance

Established vendors who have been in the business for years are guided by customer satisfaction. They listen to their customers’ needs to ensure they find the ideal loose diamond. Estate Diamond Jewelry works with a team of highly skilled experts who will match you with the diamond of your dreams. All you need to do is fill out the form at the bottom of the page and we’ll get back to you as soon as possible.

SI1 vs. SI2

round SI1 diamond side by side with round SI2 diamond.

Should you choose an SI1 or SI2 diamond? That depends on several factors.

SI1 and SI2 gems belong to the SI (Slightly Included) clarity grade. The SI1 category sits higher on the scale and features fewer imperfections.

Although SI1 diamonds have inclusions, few, if any, are visible to the naked eye. When jewelers talk about eye-clean stones, they often refer to SI1 options. SI2 diamonds have imperfections you can see without using a microscope or jeweler’s loupe.

But does this mean you should always choose an SI1 diamond over a similar SI2 option?

Not necessarily. If the blemishes are on the periphery of an SI2 gem, it will look eye-clean. It will likely be more affordable than a similar SI1 diamond. So why pass up the opportunity to get an eye-clean gem at a more affordable price? For example, this vintage ring is perfect for engagements and features a beautiful SI2 diamond.

SI1 vs. VS2

round SI1 diamond side by side with round VS2 diamond.

With SI1 diamonds, you can uncover inclusions with a loupe or a microscope. VS2 diamonds only have slight inclusions that are hard to detect at 10x magnification. The VS2 category is above the SI1 class on the grading scale, and these diamonds are usually more expensive. If you want the clean appearance of a VS2 gem but are on a tight budget, you can’t go wrong with an eye-clean SI1 diamond. These unique diamond cluster earrings have several small SI1 gems of dazzling brilliance and quality.

Top 7 Insider Tips and Tricks for Buying SI1 Clarity Diamonds

Customers Inspecting Diamond with Loupe in estate diamond jewelry Showroom

Diamond shopping can be overwhelming, but these seven insider tips will help make the process hassle-free.

  1. Closely Inspect the Diamond. When online shopping, look at high-quality images that display the diamond from all angles. You’ll understand how it performs when set in a ring and whether the shape suits you.
  2. Check the Clarity Plot: Diamonds that are 1 carat or heavier should have the clarity plot included on the lab report. The clarity plot is a map of all inclusions that pinpoints their location and nature.
  3. Buy a Vintage Piece: If you plan on reselling the diamond down the line, go for an antique. They’re rare, and collectors are eager to get their hands on them.
  4. Faint Imperfections: When looking for an eye-clean gem, aim for barely noticeable inclusions. Avoid dark crystals and aim for spread-out blemishes you can cover with the setting.
  5. Work With a Reputable Company: Reputable vendors care about their customers, often offering discounts and promo codes. Before contacting the company, hone your negotiation skills to make sure you get the best possible deal.
  6. Find the Best Shape: If you think the inclusions are too noticeable, ask to see a similar diamond in a different shape. Oval and princess cuts work wonders for masking imperfections in SI1 diamonds.
  7. Ask for the Certificate: Always examine the GIA or AGS certificate. These documents will prove that you’re indeed looking at an SI1 clarity gem.

Guide to Purchasing an SI1 Clarity Diamond Ring

hexagonal diamond engagement ring with blue sapphire halo on persons finger

Here’s what you should keep in mind when purchasing an SI1 clarity diamond ring.

  • Choose a setting that masks the inclusions.
  • Make sure the setting complements your skin tone.
  • Work with an established company.
  • Make sure the setting matches the diamond’s color, fire, and brilliance.
  • Wear your ring with pride.

Talk to a Diamond Expert

expert jeweler helping customer in estate diamond jewelery showroom

If you have any lingering questions about SI1 diamonds, fill out the contact form below and one of our experts will contact you shortly.


About Afshin Shaddaie

Afshin moved to New York City in the 1980s, and a few years later, he began his career in the fine and rare jewelry scene. He teamed up with Michael Khordipour, and they've been curating vintage jewelry ever since. He also regularly contributes to Forbes, Rapaport, CNBC, The Knot, and Insider. Afshin constantly travels to international shows and private viewing events in the hope of finding rare vintage rings that will be important enough to make an impression. He is available for appointments at our New York showroom when he's not traveling. In 2019, Afshin authored his book called The Engagement Ring Guide for Men. He is considered one of the world's foremost authorities on vintage jewelry and antique diamonds. His favorite jewelry era is Art Nouveau, and he loves rare Italian jewelry from the 1950s - 1970s. The Natural Saltwater Pearl is his favorite precious jewel.