Diamond Inclusions Guide: What Are Diamond Inclusions?

Quick Summary: Diamond inclusions are the natural internal characteristics that form gradually when a diamond grows deep within the earth. These inclusions are used to determine a diamond’s clarity grade on the GIA scale, ranging from Flawless to Included. Most inclusions are invisible to the naked eye and do not affect beauty or durability.

Diamonds, the beautiful crystals, are a miracle of geological time. They are formed over billions of years under conditions of extreme heat and pressure. Each of them carries a unique record of its formation. Those internal characteristics define the term, diamond inclusions, which are as individual as a fingerprint. Far from being flaws to be feared, they are, for the informed buyer, markers of authenticity, character, and value. 

Let’s talk about everything you need to know about diamond inclusions: what they are, how they form, how to read the diamond clarity scale, and how to choose a natural diamond that balances beauty, integrity, and investment.

What Are Diamond Inclusions? 

Diamond inclusions are the internal imperfections or characteristics that are present within different types of diamonds. But, how do they originate? They appear during the stone’s formation in the earth’s mantle, where minerals, fractures, and structural irregularities are permanently encased within the growing crystal lattice. 

Every natural diamond forms under unique conditions. This means no two diamonds are exactly alike. In many ways, inclusions act like a diamond’s natural fingerprint, making each stone unique. It is important to note that inclusions are different from blemishes. Inclusions occur inside the diamond, while blemishes appear on the surface. Together, they influence a diamond’s clarity grade, one of the four key factors used to evaluate diamond quality, alongside cut, colour, and carat weight.

Experts assess the size, number, location, and visibility of inclusions when grading a diamond. In general, diamonds with fewer or less noticeable inclusions receive higher clarity grades and are often more valuable. However, many inclusions are so small that they cannot be seen without magnification and have little to no impact on a diamond’s beauty or sparkle. 

How Do Diamond Inclusions Form? 

Natural diamond inclusions take place during the crystallisation process. This occurs approximately 150 to 200 kilometres beneath the Earth’s surface. As carbon atoms arrange themselves under temperatures exceeding 1,000 degrees Celsius and pressures over 50,000 atmospheres, foreign minerals, growth irregularities, and structural disruptions become trapped within the forming crystal. 

The most common causes of inclusion formation include: 

• Other minerals such as garnets, olivine, or pyrite are present in the surrounding mantle material
• Temperature or pressure suddenly fluctuates during crystal growth
• Internal stress fractures caused by the rapid cooling of the stone as it is carried toward the surface by volcanic activity 
• Structural irregularities in the carbon lattice (due to crystal formation) 

This is precisely why natural diamond inclusions serve as proof of authenticity. They are the geological signatures of a stone formed by nature, not a laboratory. 

Common Types of Diamond Inclusions

Diamond gemologists recognise a wide variety of inclusion types, each with distinct characteristics and clarity implications. The table below summarises the most frequently encountered types of diamond inclusions.

Among these, feathers and clouds are the most likely to affect the ‘diamond sparkle’ and structural integrity when present in significant size or in a central position. Pinpoints and needles, by contrast, are typically so minor that they have no perceptible effect on the stone’s appearance.

How Diamond Inclusions Affect Clarity

Clarity is the measure of how free a diamond is from internal inclusions and external blemishes. The GIA (Gemological Institute of America) clarity scale, the global standard adopted across the fine jewellery industry, grades diamonds on the following criteria:

• Nature: The type of inclusion present
• Number: How many inclusions the stone contains
• Size: The dimensions of each inclusion relative to the stone
• Position: Whether inclusions are centrally located or near the periphery
• Relief: How visible the inclusion is in contrast to the surrounding crystal

A single large, centrally positioned feather will lower a diamond’s clarity grade more significantly than a dozen tiny pinpoints scattered near the girdle. Position is, in many cases, as important as size. 

Diamond Clarity Scale Explained 

The GIA diamond clarity scale comprises eleven grades across six categories. Understanding this scale is essential when evaluating any natural diamond engagement ring or fine diamond jewellery purchase.

VVS diamonds, covering VVS1 and VVS2 grades, are among the most coveted clarity grades in the market. Their inclusions are so minute that even a trained gemologist requires significant effort to locate them under 10x magnification. For buyers seeking near-perfection without the extraordinary premium of Flawless or Internally Flawless stones, VVS diamonds represent an exceptional choice.

Flawless diamonds are exceptionally rare, representing fewer than 1% of all gem-quality diamonds. Their rarity makes them as much a collector’s investment as a jewellery purchase.

Do Inclusions Affect Diamond Sparkle and Beauty? 

In most cases, no. The diamond sparkle that captivates the eye is a function of cut quality, not clarity. A well-cut VS2 diamond will outshine a poorly cut VVS1 diamond every time.

The grades at which inclusions begin to affect visible beauty are:

• SI2: Some inclusions may be visible to an attentive naked eye, particularly in larger stones or under strong lighting 
• I1 to I3: Inclusions are likely visible face-up and may create hazy or dull areas that noticeably diminish brilliance 

For VS1, VS2, and all higher grades, inclusions are effectively invisible to the unaided eye. The diamond’s fire, brilliance, and scintillation remain entirely unaffected. This is why the sweet spot for real diamond engagement rings is widely considered to be the VS1 to VS2 range: exceptional beauty at a meaningful value advantage over VVS grades. 

Do Inclusions Affect Diamond Durability? 

Diamond is the hardest natural substance on earth, rating 10 on the Mohs scale. For most of the inclusions, this hardness helps by ensuring they pose no structural risk in everyday wear. 

The exceptions to this are worth noting: 

• Large feathers that extend to the surface (particularly near the girdle or culet) can create vulnerability under sharp impact 
• Chips and cavities at facet edges may worsen with heavy wear if not protected by an appropriate setting 
• Knots, which reach the surface, can affect surface durability in certain polishing scenarios 

For FL through SI1 grades, durability concerns are negligible under normal wearing conditions. Only in the I-grade range, where inclusions are large and sometimes clustered, is structural integrity a meaningful consideration. 

How Inclusions Impact Diamond Value? Diamond Inclusion Chart

Clarity is one of the principal drivers of diamond pricing, though its weight in the overall equation is often misunderstood. The diamond inclusion chart below illustrates how clarity grade correlates with value and purpose.

The most important insight for buyers is this: the difference in beauty between a VS1 and a VVS2 diamond is invisible without magnification. The difference in price, however, can be substantial. Choosing a VS1 or VS2 diamond for a real diamond engagement ring allows you to allocate more of your budget to cut quality and carat weight, the factors most visible to the admiring eye.

How to Check Inclusions in a Diamond Before Buying 

Evaluating inclusions before purchase is both a right and a responsibility for the informed buyer. The following methods are recommended:

• Request the grading certificate: A reputable diamond will come with a GIA, IGI, or equivalent certificate that details its clarity grade, inclusion type, and a plot diagram showing inclusion locations. 
• Use a jeweller’s loupe: A 10x magnification loupe allows you to examine the stone yourself. Ask your Tanishq consultant for a guided viewing. 
• Ask about inclusion position: Central inclusions under the table facet are more visible than those near the girdle. Always ask where, not just what. 
• View the stone face-up under normal lighting: This replicates how the diamond will appear when worn. A stone that looks clean to the eye in this position will look clean in life. 
• Compare grades side by side: Tanishq boutiques offer the opportunity to compare stones across clarity grades so the differences, or the absence of them, are immediately apparent. 

For mens engagement rings or any larger-format diamond jewellery where the stone is a prominent focal point, stepping up to a VS1 or VVS2 grade is a worthwhile consideration as inclusions become relatively more visible in larger stones.  

Diamond Expertise Centre (DXC): Confidence You Can See 

At Tanishq, transparency goes beyond certification. The Diamond Expertise Centre (DXC) lets you verify any natural diamond yourself, free of cost, using advanced, lab-grade technology. You can confirm your diamond’s origin, examine its unique clarity characteristics, compare them with the clarity grade on the certificate, experience the light performance of solitaires, and verify its authenticity through its Unique Identification Number (UID) and the Tanishq logo.

A trained gemmologist guides you through every step, empowering you to make an informed choice based on proof, not just trust.

Light Scope
Experience the brilliance, fire, and scintillation of Tanishq solitaires. Celeste solitaires are designed to deliver exceptional light performance, making their sparkle even more remarkable.

Clarity Viewer
Observe your diamond under magnification to see its unique inclusions and verify whether its clarity grade, whether VVS, VS, or SI, matches the certificate.

Diamond Caratmeter
Check the origin of your diamond and verify whether it is natural.

Marking Viewer
Authenticate your diamond by viewing its Unique Identification Number (UID) along with the Tanishq logo inscribed on the diamond.

The Diamond Expertise Centre is available at 171 Tanishq DXC stores across India, with more locations being added. Visit your nearest DXC and experience complete transparency before making your choice, based on proof rather than promise.  

Conclusion 

Diamond inclusions are not imperfections. They are the earth’s own record of a stone’s extraordinary journey from the depths of the mantle to the hand that will wear it. Understanding them transforms a purchase into a conversation between buyer and stone, one informed by knowledge rather than mystique.

The right clarity grade for any diamond depends on your personal priorities: whether beauty, rarity, durability, or value carries the greatest weight in your decision. Across all these dimensions, the guidance of a trusted jeweller makes an immeasurable difference.

At Tanishq, every natural diamond is certified, transparently billed, and selected against standards that go far beyond industry norms. We invite you to visit your nearest Tanishq boutique, where our consultants will walk you through our complete diamond ring collection and help you find the stone that speaks to your story.