Diamond Clarity Scale Explained: FL to I3 in Plain English
The diamond clarity scale runs from Flawless (FL) at the top to Included 3 (I3) at the bottom, with eleven grades in total. The grade describes the number, size, and visibility of internal characteristics (inclusions) and surface blemishes in the diamond. For most buyers, the practical question is not where a diamond falls on the full scale, but whether it is eye-clean — meaning no inclusions are visible to the naked eye at normal viewing distance.
TL;DR: The diamond clarity scale has eleven grades from Flawless to I3, but most buyers choosing a diamond for an engagement ring will find their sweet spot in the VS1 to SI1 range. An eye-clean VS2 or SI1 diamond in most shapes gives excellent appearance at a significantly lower cost than IF or FL grades. The GIA and IGI grading scales are equivalent — both are internationally recognised.
The Full Diamond Clarity Scale
| Grade | Name | What it means |
|---|---|---|
| FL | Flawless | No inclusions or blemishes under 10x magnification |
| IF | Internally Flawless | No inclusions; minor surface blemishes only |
| VVS1 | Very Very Slightly Included 1 | Inclusions extremely difficult to see under 10x |
| VVS2 | Very Very Slightly Included 2 | Inclusions very difficult to see under 10x |
| VS1 | Very Slightly Included 1 | Inclusions difficult to see under 10x; invisible to naked eye |
| VS2 | Very Slightly Included 2 | Inclusions somewhat difficult to see under 10x; invisible to naked eye |
| SI1 | Slightly Included 1 | Inclusions easy to see under 10x; usually invisible to naked eye |
| SI2 | Slightly Included 2 | Inclusions very easy to see under 10x; occasionally visible to naked eye |
| I1 | Included 1 | Inclusions visible to naked eye; may affect brilliance |
| I2 | Included 2 | Inclusions clearly visible; affect brilliance |
| I3 | Included 3 | Inclusions very obvious; significantly affect transparency and brilliance |
What “Eye-Clean” Actually Means
Eye-clean refers to a diamond in which no inclusions or blemishes are visible when the stone is viewed with the naked eye from a normal viewing distance — roughly 20 to 30cm, not pressed against the eye. This is the standard by which most engagement ring diamonds are practically assessed.
A diamond does not need to be Flawless to be beautiful. The vast majority of people, including jewellers working without magnification, cannot see the difference between an FL diamond and a VS1 diamond in normal lighting. The clarity grade is primarily relevant under 10x magnification — the standard used by gemologists.
Which Clarity Grade Should You Buy?
FL and IF — genuinely rare and genuinely expensive. The premium over VVS1 is significant, and the visual difference in a mounted ring is undetectable to the naked eye. Unless you specifically value rarity and perfection for its own sake, this is not where budget is well spent.
VVS1 and VVS2 — excellent diamonds with inclusions that challenge even trained gemologists under magnification. Eye-clean in every practical sense. The right choice if you want near-perfection without paying the FL premium, or if the diamond is large enough (2ct+) that inclusions become easier to spot.
VS1 and VS2 — the most practical range for engagement ring diamonds. Inclusions are invisible to the naked eye in almost all cases; visible under 10x magnification but difficult to find even then. VS2 is the grade most experienced jewellers recommend as the best value balance for a high-quality engagement ring diamond.
SI1 — usually eye-clean, particularly in brilliant cuts (round, oval, cushion, pear) where the faceting pattern disperses and hides inclusions effectively. Should be assessed individually — not all SI1 diamonds are equal, and the position of an inclusion matters as much as its size.
SI2 — occasionally eye-clean in brilliant cuts; rarely eye-clean in step cuts (emerald, Asscher). Each stone must be assessed individually and carefully. At this grade, inclusions begin to affect light return in some stones.
I1 to I3 — inclusions visible to the naked eye. Not recommended for an engagement ring where appearance is the priority.
How Shape Affects Clarity
The way a diamond is cut affects how visible inclusions are. Brilliant cuts — round, oval, cushion, pear, radiant, marquise — scatter light in a way that masks inclusions very effectively. A VS2 round brilliant will typically look cleaner to the eye than a VS2 emerald cut, because the step-cut faceting of the emerald cut creates long, clear windows into the stone rather than dispersing light.
For step cuts (emerald and Asscher), VS1 or above is a safer recommendation. For brilliant cuts, VS2 to SI1 represents the best value range for most budgets.
GIA vs IGI Clarity Grading
GIA (Gemological Institute of America) and IGI (International Gemological Institute) use the same clarity scale and the same grading methodology. Both are internationally recognised and trusted. IGI tends to be the dominant certification body for lab-grown diamonds; GIA is more commonly associated with natural diamonds, though GIA now certifies lab-grown stones as well.
At À Vie Diamonds, all centre stones are IGI or GIA certified. The certificate accompanies every commission. See our clarity guide for more detail on how inclusions are categorised and plotted on a diamond certificate.
What This Means for Your Budget
Clarity is one of the four factors (alongside cut, colour, and carat) that determines a diamond’s price. Moving from VS1 to SI1 in an equivalent round brilliant can reduce the stone price by 20 to 35 per cent with no visible difference to the naked eye — a meaningful saving that can be reallocated to carat weight or cut quality.
For most engagement ring buyers with a specific budget, we recommend prioritising cut (which determines brilliance) and colour first, then selecting the highest clarity that fits the remaining budget while remaining eye-clean.
Visit our carat guide and cut guide to understand how all four factors interact, or contact us for a personalised stone recommendation.
Frequently Asked Questions
What is the best clarity for a diamond engagement ring? For most buyers, VS2 to SI1 in a brilliant-cut diamond gives the best value — eye-clean with no visible inclusions, at a meaningfully lower price than VVS or FL grades. For step cuts (emerald, Asscher), VS1 or above is a safer starting point.
What does eye-clean mean? Eye-clean means no inclusions or blemishes are visible when the diamond is viewed with the naked eye at normal viewing distance (approximately 20 to 30cm). It is the practical standard most buyers use, as inclusions only visible under 10x magnification have no effect on how the ring looks when worn.
What is the difference between VS1 and VS2? Both VS1 and VS2 are eye-clean grades. VS1 inclusions are slightly more difficult to see under 10x magnification than VS2, but the visual difference when mounted in a ring is imperceptible to the naked eye. The price difference can be 10 to 20 per cent — choosing VS2 is often the better value decision.
Is FL (Flawless) worth buying for an engagement ring? For most buyers, no. FL diamonds command a significant premium over VVS1 and IF grades, but the visual difference in a mounted ring is undetectable to the naked eye.
Does clarity affect a diamond’s sparkle? At VS2 and above, clarity does not affect brilliance — the inclusions are too small to interfere with light return. At SI2 and below, some inclusions can begin to affect transparency. At I1 to I3, inclusions are visible and do meaningfully reduce brilliance.
Last reviewed: July 2026 · À Vie Diamonds