Diamond Clarity Explained: From VVS to SI

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Diamond clarity grades how few internal marks (inclusions) and surface marks (blemishes) a diamond has — from Flawless down to Included. The key truth: above a certain grade, none of them are visible to the naked eye. Here is the scale, where it came from, what the inclusions actually are, how a grader arrives at a single letter, which shapes hide inclusions and which reveal them, and where the value sits.

Key takeaways

• Clarity runs FL → IF → VVS1–VVS2 → VS1–VS2 → SI1–SI2 → I1–I3.
• Most inclusions are microscopic — invisible without 10x magnification.
• 'Eye-clean' — no inclusions visible to the naked eye — is the practical bar most buyers want, and it is not printed on any certificate.
• A grade is not one number. It reflects the size, number, position, nature and relief of what the grader finds.
• Step cuts (emerald, asscher) show inclusions more, so they need higher clarity; brilliant-faceted shapes are far more forgiving.
• Clarity is graded under 10x magnification by a trained gemologist, the same standard whether the diamond is mined or lab-grown.
• Montare's floor is VVS1–VVS2 — beyond eye-clean, with room to spare, and never clarity-enhanced.

The clarity scale

Grade	Meaning	Eye-clean?
FL / IF	Flawless / Internally Flawless — nothing under 10x	Always
VVS1–VVS2	Very, very slight — extremely hard to see even at 10x	Always
VS1–VS2	Very slight — minor at 10x	Almost always
SI1–SI2	Slight — visible at 10x, sometimes to the eye	Sometimes — depends on the stone and the shape
I1–I3	Included — visible to the naked eye	No

Where the clarity scale came from

The scale is younger than most people assume. Before the 1950s there was no shared vocabulary for diamond quality: a stone could be described as "first water" or "commercially clean" by one dealer and something else entirely by the next, and a buyer had no way to compare. In 1953 Richard T. Liddicoat and colleagues at the Gemological Institute of America introduced a practical grading system built on four factors — colour, clarity, cut and carat weight — originally as a teaching tool for GIA's own diamond grading class. It included the D-to-Z colour scale and the Flawless-to-I3 clarity scale still in use today, and GIA issued its first diamond grading reports the same year.

Two things follow from that history. First, the scale was designed to describe what a trained grader sees under a loupe, not what a wearer sees across a dinner table — which is why 'eye-clean' is a separate idea the certificate never mentions. Second, because it started as a shared language rather than a physical measurement, the boundaries between adjacent grades are judgements made by people to a documented standard. That is a strength, not a weakness: it is the reason a VS1 from a reputable laboratory means roughly the same thing anywhere in the world. It is also why the laboratory on your report matters as much as the letters on it.

How clarity is actually graded

A gemologist examines the diamond under 10x magnification — the industry-standard loupe power — and records every inclusion and blemish, then assigns a grade based on the least favourable combination of what is there, not an average. GIA sets out five factors that decide how much any single characteristic drags the grade down.

Factor	What the grader is judging	Why it changes the grade
Size	How large the characteristic is	The larger it is, the greater the impact — this is the single biggest lever
Number	How many characteristics are easily seen	Fewer means a higher grade; a scattering of tiny marks can cost more than one slightly larger one
Position	Where it sits within the stone	Directly under the table is the worst place to be; the same inclusion near the girdle counts for far less
Nature	What type it is, and whether it affects durability	A feather reaching the surface is treated differently from a pinpoint sealed inside
Colour or relief	How distinctly it stands out against the surrounding diamond	A dark, high-relief crystal is penalised more than a faint, transparent one of the same size

This is why two stones can carry the same grade and still look subtly different under a loupe: the grade is a category, not a single fixed appearance. Both laboratories use the same 10x standard, but they no longer report it the same way. IGI grades lab-grown diamonds on the full FL-to-I3 scale exactly as it grades mined stones. Since 1 October 2025, GIA has not issued specific clarity grades on lab-grown diamonds at all, replacing them with a two-tier Premium or Standard classification in which Premium means VVS or better and Standard means VS. On a mined diamond, both still publish the full scale. We cover that change in GIA's 2025 lab-grown grading changes and compare the two reports in IGI vs GIA for lab-grown diamonds.

Common types of inclusions

Type	What it is
Pinpoint	A tiny crystal, often appearing as a small dot — the most common inclusion at high clarity grades
Feather	A small internal fracture, named for its feathery appearance under magnification
Cloud	A cluster of tiny pinpoints too small to distinguish individually, giving a hazy area
Crystal / included mineral	A tiny mineral crystal trapped inside the diamond during formation
Graining	Faint internal lines from irregular crystal growth — common in both mined and lab-grown stones

These are the same features graders mark on the plot printed on your certificate — see how to read a diamond certificate for how to interpret it. Two are worth singling out. A feather is the only common inclusion with a durability question attached: sealed well inside the stone it is inert, but one breaking the surface at a vulnerable point is the reason a grader weighs nature as well as size. A cloud is the one that can affect appearance out of proportion to its grade — a large, diffuse cloud can take the light off a stone that still reads well on paper, which is exactly what a grade alone cannot tell you.

Which shapes hide inclusions — and which reveal them

Clarity is the one C whose practical requirement changes with shape. Brilliant faceting scatters light in many directions and buries small marks inside the sparkle. Step cuts do the opposite: long, open, parallel facets act like windows into the stone, so anything inside is on show. Both effects are about the faceting family, not the quality of the cut.

Shape	Faceting family	How forgiving
Round	Brilliant	Most forgiving — maximum light scatter across 57 or 58 facets
Cushion	Brilliant (often 'crushed ice')	Very forgiving — the broken-up light pattern conceals small marks well
Radiant	Brilliant, in a cut-corner outline	Very forgiving — brilliant faceting despite the rectangular shape
Oval	Brilliant	Forgiving — watch the centre, where the eye settles
Pear	Brilliant	Forgiving — the point is the area to check
Marquise	Brilliant	Forgiving — as with pear, the two points deserve a look
Emerald	Step cut	Least forgiving — the open table shows everything, so clarity has to be higher

The practical read: on a brilliant-faceted shape, clarity is where a buyer has genuine room to be strategic. On an emerald cut — the one step cut in our line — it is not. That single asymmetry explains most of the confusing advice online, where a rule written for one shape gets repeated as though it applied to all seven.

Clarity in lab-grown diamonds

Lab-grown diamonds form under controlled conditions rather than in the earth, which changes the typical mix of inclusions slightly — CVD-grown stones, for instance, can show a form of graining tied to their layer-by-layer growth process, while HPHT-grown stones are more likely to carry small metallic flux inclusions from the growth cell. The grading scale, the 10x standard, and what counts as eye-clean are identical to mined diamonds. If you want the mechanics of both growth methods, we set them out in how lab-grown diamonds are made: CVD vs HPHT.

A well-documented myth is that lab-grown diamonds go "cloudy" over time; they do not, because diamond is chemically inert and cannot change — see our full answer in do lab-grown diamonds get cloudy over time? The inclusions a stone is born with are the inclusions it will still have in fifty years.

Clarity treatments — and why we never use them

Some diamonds on the market have had their clarity improved after cutting. The two common methods are fracture filling, where a glass-like substance is drawn into a surface-reaching feather to make it far less visible, and laser drilling, where a microscopic channel is bored to a dark inclusion so it can be bleached out. Laser drilling is permanent; fracture filling is not, and can be damaged by the heat of a routine repair or by some cleaning chemicals. GIA does not issue standard grading reports for fracture-filled diamonds at all, and treatment must be disclosed at every point of sale.

The point is not that treated stones are dishonest — properly disclosed, they are a legitimate budget product. The point is that a treated SI stone and an untreated one can carry the same printed letter while being entirely different purchases, and the difference lives in the fine print rather than in the grade. Montare's stones are untreated, and at a VVS1–VVS2 floor there is nothing that clarity enhancement could usefully do to them. It is one of several questions that stops being relevant once the standard is set high enough.

What does 'eye-clean' mean?

'Eye-clean' means no inclusions are visible to a normal eye at a normal viewing distance — usually taken as about 25–30 cm, roughly how far a ring sits from your face when you look at your own hand. It is the only clarity threshold that affects daily wear, and it appears on no certificate anywhere, because it is a judgement about appearance rather than a graded measurement. Many VS and even some SI stones are eye-clean. Above that threshold, paying for a higher grade buys assurance and certificate strength, not a visible difference.

Which clarity should you choose?

For most shapes, a VS stone is reliably eye-clean and excellent value. The exception is step cuts — emerald and asscher — whose large, open facets act like windows and reveal inclusions, so they reward higher clarity. Size matters too: the same inclusion in a three-carat stone is physically larger and sits under a bigger table than it would in a one-carat stone, which is part of why clarity expectations rise as carat weight does. We explain why we set our floor where we did in why three carats.

Where the diamond's other qualities are exceptional, clarity is the C where you can be most strategic. The C you should never compromise is cut, which governs how the stone actually returns light — see why Triple Excellent matters, the role of table and depth percentages in ideal cut, table and depth explained, and how the four factors trade off in the 4Cs explained. Colour is the other place buyers often over- or under-spend; we cover it in diamond colour explained.

Why Montare sets a VVS floor

We set clarity at VVS1–VVS2 — above eye-clean for every shape, including step cuts — because the brand is built on a standard you never have to second-guess. It sits alongside the rest of the floor: D–E colour, Triple Excellent cut, ideal proportions with table and depth percentages held in the ideal range for that specific shape, three carats minimum, and IGI certification. Table and depth are the two numbers that decide whether a stone throws light rather than leaks it, and they are not the same across shapes — which is why we publish them per shape on our standards rather than quoting one universal figure.

Lab-grown is what makes that floor attainable at three carats: a VVS, D–E, Triple Excellent, three-carat mined diamond would cost many times more. The process is straightforward — you describe what you are looking for in shape, size and character, and we go and source the best stone that clears the standard. Our goldsmiths then cast, set and polish the ring by hand in Toronto. Nothing is built for stock, so no ring is hurried along to clear a shelf or catch a shipping cut-off; the aim is never to get a piece out the door as fast as possible, it is to make the best piece possible. With Montare, the highest grades are the starting point, not an upsell.

Frequently asked questions

What is the best diamond clarity?

FL and IF are the highest, but they look identical to VVS to the naked eye. For value, an eye-clean stone (VS, or VVS for total assurance and step cuts) is the smart choice.

What does eye-clean mean?

No inclusions are visible to the naked eye at normal viewing distance — the only clarity threshold that affects how the diamond looks in wear.

Is VVS clarity worth it?

VVS is beyond eye-clean, so visually it is not necessary for most shapes — but it guarantees a clean stone for step cuts and adds certificate assurance. Montare includes it as standard.

Does clarity affect a diamond's sparkle?

Not meaningfully at eye-clean grades — sparkle is governed by cut. Only heavily included stones (SI2 and below) can dull brilliance.

What are the most common types of inclusions?

Pinpoints (tiny crystals), feathers (small internal fractures), clouds (clusters of pinpoints), included crystals, and graining are the most common. Nearly all are invisible without 10x magnification at VS clarity and above.

Which diamond shape hides inclusions best?

Brilliant-faceted shapes hide them best because the scattered light pattern breaks up small marks — round is the most forgiving, with cushion and radiant close behind. Step cuts such as emerald are the least forgiving, because the large open facets act as windows into the stone.

Do lab-grown diamonds have different inclusions than mined diamonds?

The mix can differ slightly — CVD-grown stones sometimes show a form of graining tied to their growth process, and HPHT-grown stones can carry small metallic inclusions — but the same 10x grading scale and eye-clean standard apply to both, and lab-grown diamonds do not develop new inclusions or cloud over time.

How is clarity actually graded?

A gemologist examines the stone under 10x magnification and records every inclusion and blemish by size, number, position, nature and relief, then assigns a grade based on the least favourable characteristics found — the same process IGI and GIA use for mined diamonds.

Every Montare diamond starts at VVS. Build one in the ring builder or book a consultation.