Beyond the Grade: Decoding How Inclusions Shape Your Diamond’s Clarity

What They Are, Why They Exist, and How Much They Actually Matter

Every diamond tells the story of how it was formed, and inclusions are part of that story. The word inclusion tends to make shoppers nervous, conjuring images of visible flaws that compromise the beauty of a stone. The reality is far more nuanced than that. Most inclusions are microscopic, most are invisible to the naked eye, and understanding them properly is one of the most powerful tools available to an engagement ring buyer who wants to make a smart, confident purchase.

Shop Engagement Rings Shop Lab Grown Jewelry

IN THIS GUIDE

01 What Are Diamond Inclusions?  02 How Inclusions Form in Natural Diamonds  03 How Inclusions Form in Lab Grown Diamonds 04 The Different Types of Diamond Inclusions  05 The Clarity Grading Scale Explained  06 What Is Eye Clean and Why Does It Matter?  07 How Inclusions Affect Value and Beauty  08 Inclusions Shape Your Diamond’s Clarity

The experts you can trust: Clarity is one of the most misunderstood of the 4 Cs, and it is also one of the areas where buyers most commonly overspend without gaining any visible benefit. We cover every aspect of diamond inclusions so you can make a clarity decision that is genuinely informed rather than driven by fear of imperfection. Keep reading, or reach out to our team today for personalized guidance.

What Are Diamond Inclusions?

A diamond inclusion is any internal characteristic present within the body of a diamond. The word comes from the Latin includere, meaning to enclose, and describes any material or structural irregularity that became trapped or developed inside the stone during its formation. Inclusions are distinct from blemishes, which are surface characteristics on the exterior of the diamond rather than features within its interior.

Inclusions take many different forms. Some are tiny crystals of other minerals that were present during the diamond's growth and became encased within the structure of the stone. Some are small fractures or feathers within the crystal lattice. Some are clouds of microscopic pinpoint marks that are only detectable under magnification. Some appear as fine needles, graining, or knots of crystal that grew as part of the diamond itself.

The vast majority of inclusions in commercially sold diamonds are invisible without magnification. A trained gemologist examining a stone under a ten times loupe or a microscope may be able to identify and map every inclusion in a stone that appears completely flawless to anyone looking at it with the naked eye. This gap between what is detectable under magnification and what is actually visible in real life is the most important practical concept in the entire clarity discussion.

Inclusions are not defects in the sense of something going wrong. They are the natural record of how a diamond grew. No two diamonds have identical inclusion patterns, which means inclusions function as a unique fingerprint for every stone. A diamond's inclusion map, documented on its grading certificate, is one of the tools gemologists use to confirm that a certified stone has not been switched or substituted.

Shop Engagement Rings

How Inclusions Form in Natural Diamonds

Natural diamonds form deep in the earth's mantle under conditions of extreme heat and pressure, at depths of roughly one hundred miles below the surface. The process takes place over periods ranging from one billion to three billion years. During this extraordinarily long formation process, the growing diamond crystal can incorporate other minerals, encounter fractures from seismic events, or develop internal structural irregularities as a natural consequence of its environment.

  • When another mineral crystal such as garnet, olivine, or even a fragment of another diamond is present in the carbon-rich environment where a diamond is growing, it can become encased within the growing stone. This is how crystal inclusions form. They are literally other minerals that were in the wrong place at the right time during the diamond's billion-year growth process.
  • Feathers and fractures form when the diamond crystal experiences stress, either from sudden temperature changes, pressure shifts, or seismic activity over geological timescales. These are essentially small cracks within the crystal structure. Some are entirely healed and sealed, with no risk of propagation. Others are open fractures that require careful handling.
  • Growth-related inclusions like graining, twinning wisps, and clouds form as a result of irregularities in the crystal growth process itself. When the conditions of growth shift slightly, the lattice structure of the diamond can develop internal planes or regions where the crystal grew in a slightly different orientation or density.

The presence of inclusions in a natural diamond is essentially universal.

  • Flawless natural diamonds, those with no inclusions visible under ten times magnification, are extremely rare and command significant price premiums that reflect that rarity.
Shop Engagement Rings

How Inclusions Form in Lab Grown Diamonds

Lab grown diamonds are created through two primary methods,

  • High Pressure High
  • Temperature and
  • Chemical Vapor Deposition

Each produces its own characteristic inclusion types that differ in some ways from those found in natural diamonds.

  • In High Pressure High Temperature growth, a small diamond seed is placed in a chamber with carbon-rich material and subjected to conditions that mimic the heat and pressure of the earth's mantle. The process uses a metal catalyst, typically iron, nickel, or cobalt, to facilitate the growth of the diamond. Metallic flux inclusions, which appear as small dark or reflective particles under magnification, are the most distinctive inclusion type associated with this growth method. They are typically very small and rarely affect the face-up appearance of the finished stone.

  • In Chemical Vapor Deposition growth, a diamond seed is placed in a chamber flooded with carbon-rich gas. Carbon atoms are deposited layer by layer onto the seed as the gas breaks down, gradually building the diamond. CVD-grown diamonds can develop inclusions related to the layer-by-layer growth process, including pinpoints, clouds, and internal graining. Some CVD diamonds also show strain patterns that are related to the growth conditions rather than external stress.

The practical significance of lab grown diamond inclusions is the same as for natural diamonds. What matters most is whether the inclusions are visible to the naked eye under normal viewing conditions.

  • A lab grown diamond with a VS2 clarity grade looks just as clean and beautiful in real life as a natural diamond with the same grade.
  • The origin of the inclusion does not affect how the stone looks when worn.

The Different Types of Diamond Inclusions

Crystal Inclusions

A crystal inclusion is a mineral crystal that was encased within the diamond during its growth.

  • Crystals can be colorless, white, black, or tinted depending on the mineral they are composed of. Small colorless crystals within the body of a diamond are generally among the least visible and least impactful inclusion types.
  • Black crystal inclusions, sometimes composed of graphite or dark mineral deposits, can be more visible in certain positions within the stone.

Feathers

A feather is a small fracture within the diamond crystal. The name comes from the white, feathery appearance these fractures can display under reflected light.

  • Small feathers confined to the interior of the stone and away from the girdle or surface are typically of minimal concern.
  • Larger feathers that reach the surface of the stone or are positioned near the girdle require more careful evaluation because they represent a potential vulnerability under physical stress.

Clouds

A cloud is a cluster of tiny pinpoint inclusions grouped closely enough together that they create a hazy or milky appearance in that region of the stone.

  • Individual pinpoints are essentially invisible, but a dense cloud can affect light transmission in its immediate area.
  • Very dense clouds are one of the few inclusion types that can affect the transparency and brilliance of a diamond in ways that may be visible without magnification, which is why some grading certificates note that clarity is based on clouds not shown.

Needles

A needle inclusion is a long, thin crystal that appears as a bright, hair-like line within the stone. Needles are typically white or transparent and are visible under magnification but rarely visible to the naked eye unless they are very large or positioned in a highly visible location near the table of the stone.

Pinpoints

A pinpoint is among the smallest and least significant inclusion types. It appears as a tiny white or black dot within the stone, visible only under magnification.

  • A single pinpoint has virtually no impact on the beauty or durability of the diamond.
  • Dense groupings of pinpoints form the clouds described above.

Graining

Graining refers to irregularities in the crystal growth structure of the diamond, appearing as faint lines or planes within the stone. Internal graining is caused by irregular crystal growth and can create a slight haziness or visual texture in certain lighting conditions. It is a growth characteristic rather than a foreign material and is relatively common in both natural and lab grown diamonds.

Twinning Wisps

Twinning wisps are a series of pinpoints, clouds, and crystals that have formed along a twinning plane, a boundary where two diamond crystals grew together in different orientations. They appear as a ribbon or wisp of inclusions following a curved or irregular path through the stone. Twinning wisps are commonly associated with fancy-shaped diamonds and can range from entirely invisible to clearly visible depending on their density and position.

Knots

A knot is a crystal inclusion that extends to the surface of the diamond after faceting, meaning the inclusion is not entirely enclosed within the stone. Knots are among the more significant inclusion types because they can affect the structural integrity of the stone at that surface point and may be visible as a slight raised area on the polished surface.

Cavities

A cavity is a small opening on the surface of the diamond, either present from the original rough stone or created when a surface-reaching crystal falls out during the cutting and polishing process. Cavities can collect dirt and oils over time, which can make them more visible in worn jewelry. A cavity that is small and confined to a less visible area of the stone is typically of limited practical concern.

Chips

A chip is a small piece of diamond that has been lost from the surface, usually at the girdle, culet, or facet junction, through impact or wear. Unlike most inclusions, which are present from the formation of the stone, chips are typically damage that occurs after the diamond has been cut. A chipped diamond should be examined carefully by a jeweler to assess whether the damage affects structural integrity or can be addressed through recutting.

The Clarity Grading Scale Explained

The clarity grading scale used by major gemological institutions divides diamonds into categories based on the size, number, nature, position, and visibility of their inclusions and blemishes. The scale was developed by the Gemological Institute of America and has become the universal standard across the diamond industry.

Flawless (FL)

  • No inclusions or blemishes visible under ten times magnification to a skilled grader. Flawless diamonds are extraordinarily rare and command a significant price premium that reflects their scarcity rather than any visible difference from lower grades in everyday wear.

Internally Flawless (IF)

  • No inclusions visible under ten times magnification. Minor surface blemishes may be present. Internally flawless diamonds are extremely rare and similarly priced at a premium that reflects rarity rather than visible beauty advantages over lower grades.

Very Very Slightly Included (VVS1 and VVS2)

  • Inclusions are so minute that they are extremely difficult for a skilled grader to detect under ten times magnification.
  • VVS diamonds are an excellent choice for buyers who want the confidence of a very high clarity grade without paying the premium for FL or IF. In everyday wear, VVS diamonds are completely indistinguishable from flawless stones.

Very Slightly Included (VS1 and VS2)

  • Inclusions are minor and range from difficult to somewhat easy for a skilled grader to see under ten times magnification. VS diamonds represent one of the best overall values in the clarity range.
  • They are eye clean in virtually all cases, carry strong certification grades, and are priced meaningfully below VVS grades without any sacrifice in visible appearance.

Slightly Included (SI1 and SI2)

  • Inclusions are noticeable to a skilled grader under ten times magnification.
  • SI1 diamonds are frequently eye clean, meaning the inclusions are not visible without magnification under normal viewing conditions.
  • SI2 diamonds require more careful individual evaluation.
  • Some SI2 stones are eye clean, while others have inclusions that are visible to a careful observer without magnification, particularly in larger carat weights or step-cut shapes where the open, mirror-like faceting makes inclusions easier to detect.

Included (I1, I2, and I3)

  • Inclusions are obvious under ten times magnification and may affect transparency and brilliance.
  • I1 diamonds may still be acceptable for some buyers depending on the specific inclusions and their position, but I2 and I3 diamonds typically have inclusions that are clearly visible to the naked eye and may compromise the structural integrity and light performance of the stone. These grades are not generally recommended for engagement rings.

What Is Eye Clean and Why Does It Matter?

Eye clean is an informal but extremely useful term that describes a diamond whose inclusions are not visible to the unaided eye under normal viewing conditions.

  • A diamond does not need a flawless or internally flawless clarity grade to be eye clean.
  • The vast majority of VS1, VS2, and many SI1 diamonds are completely eye clean, meaning that anyone looking at the ring in everyday life will see a stone that appears perfectly clear and brilliant.

The practical significance of this concept is enormous for buyers working with a budget.

  • The difference in price between a VVS1 and a VS2 diamond of the same cut, color, and carat weight can be substantial, and yet the two stones will look identical to everyone who sees the ring in real life.
  • The premium paid for the VVS1 grade exists on the grading certificate, not on the finger.

There are important nuances to the eye clean evaluation that depend on the specific stone and its shape.

  • Step-cut shapes like emerald and Asscher cuts have large, flat facets that function like mirrors and make inclusions more visible than the intricate faceting of brilliant cuts.
  • An SI1 emerald cut requires much more careful individual evaluation than an SI1 round brilliant because the facet structure of the emerald cut conceals inclusions far less effectively. Oval, pear, and marquise cuts have bowtie areas near their points where inclusions can sometimes be more visible than in the center of the stone.

The most reliable way to evaluate whether a specific diamond is eye clean is to request high-resolution photography or video of the actual stone under magnification, and then ask the jeweler to confirm that the inclusions are not visible to the naked eye.

Most reputable online diamond retailers provide this as standard, and in-person jewelers can show you the stone under normal viewing conditions before you commit.

How Inclusions Affect Value and Beauty

The relationship between inclusions, value, and visual beauty is not as straightforward as the clarity grading scale might suggest. Understanding this relationship properly is what separates buyers who overpay for clarity from those who allocate their budget wisely across all four Cs.

Inclusions and Value

Diamond clarity has a direct and measurable effect on price.

  • Moving up the clarity scale from SI1 to VS2 to VS1 to VVS2 to VVS1 to IF to FL produces progressively higher prices at each step, and the price increases are significant.
  • For natural diamonds in popular sizes and shapes, moving from an eye-clean SI1 to a VVS2 of equivalent cut, color, and carat can increase the price by thirty to fifty percent or more depending on the specific grades and the market at the time of purchase.

The question every buyer should ask is whether that price difference produces any visible benefit for the person wearing the ring in everyday life. In most cases above the SI1 range, for brilliant-cut diamonds of standard carat weights, the honest answer is no.

  • The higher clarity grade exists on the certificate and in the laboratory assessment. It does not exist in the appearance of the ring.

This does not mean clarity is irrelevant to value. A well-documented high-clarity diamond carries a recognized grade that contributes to its resale and replacement value. But for buyers whose primary concern is how the ring looks when worn rather than its certificate specifications, allocating budget that might otherwise go toward an unnecessary clarity upgrade toward a better cut quality or a larger carat weight in an eye-clean grade almost always produces a more beautiful result.

Inclusions and Light Performance

Most inclusions have a minimal effect on a diamond's light performance and brilliance. The small percentage of the diamond's volume occupied by typical inclusions in the VS and SI ranges does not meaningfully interfere with the optical performance of the stone. The exception involves specific inclusion types in specific positions.

  • A large feather positioned directly beneath the table of the stone, a very dense cloud covering a significant portion of the interior, or a twinning wisp in a step-cut diamond in a particularly visible position can all affect how the stone performs in ways that may be subtly detectable in certain lighting conditions.

This is another reason why evaluating specific stones rather than relying solely on clarity grades is so valuable.

  • Two diamonds with the same clarity grade can look very different depending on the nature and position of their inclusions, which is information the grade alone does not convey.

Explore More Guides

The Best Way to Measure Ring Size
Moissanite & Diamond: Understanding the Differences
Comparing lab grown & natural diamonds
The 4 c's of buying diamonds
How to Care for Your Engagement Ring
finance your engagement ring
Celebrity engagement rings and their cuts

More To Explore

This is where you can introduce the collection’s overall theme, product range, or highlight special features.
Emerald
This is where you can introduce the collection’s overall theme, product range, or highlight special features.
Marquise
This is where you can introduce the collection’s overall theme, product range, or highlight special features.
Oval
This is where you can introduce the collection’s overall theme, product range, or highlight special features.
Pear