Diamond Clarity Guide
Clarity measures what a diamond carries inside it, its inclusions, and on its surface, its blemishes. The fewer there are and the harder they are to see, the higher the grade.
What is clarity grading?
A grader examines the stone under 10x magnification, the standard for the trade, and weighs everything found by its size, nature, number, position and relief. The grade describes how visible those characteristics are at 10x, not simply how many there are.
- Inclusions
- Inside the stone: crystals, feathers, pinpoints and clouds formed as it grew.
- Blemishes
- On the surface: polish lines, nicks and scratches, often from cutting or wear.
Two laboratories, one scale
Natural stones we list are graded predominantly by GIA, lab-grown predominantly by IGI. Both use the same FL–I3 scale under the same 10x standard, so a VS1 on one report sits at the same point on the scale as a VS1 on the other, whatever the stone's origin.
How strictly each laboratory applies the scale is debated in the trade. Read the grade as a reliable starting point, then look at the plot and the stone.
The clarity scale
Eleven grades in five groups, from Flawless to Included. Each view below is a round brilliant under a 10x loupe; stones on hand this week are listed under their report grade.
FL / IF
Flawless / Internally Flawless
No inclusions visible to a skilled grader at 10x. FL shows no blemishes either; IF may show minor surface blemishes.
- FL
- None natural · None lab-grown
- IF
- None natural · 2 lab-grown
VVS1 / VVS2
Very, Very Slightly Included
Inclusions so slight they are extremely difficult for a skilled grader to find at 10x.
- Pear Brilliant 2.00 ct · VVS2, lab-grown
- VVS1
- 5 natural · 40 lab-grown
- VVS2
- 9 natural · 767 lab-grown
VS1 / VS2
Very Slightly Included
Minor inclusions, difficult to somewhat easy to see at 10x. Almost never visible to the eye.
- Round 1.50 ct · VS1, lab-grown
- Asscher 1.03 ct · VS1, natural
- Oval 1.00 ct · VS2, natural
- Emerald Cut 2.77 ct · VS2, lab-grown
- VS1
- 26 natural · 889 lab-grown
- VS2
- 44 natural · 338 lab-grown
SI1 / SI2
Slightly Included
Inclusions noticeable at 10x. Sometimes visible to the eye, more often in SI2 and in larger stones.
- Radiant 1.00 ct · SI1, natural
- SI1
- 22 natural · 69 lab-grown
- SI2
- 8 natural · 8 lab-grown
I1 / I2 / I3
Included
Inclusions obvious at 10x and usually to the eye. They can affect transparency, brilliance and, at I3, durability.
- I1
- None natural · 1 lab-grown
- I2
- 1 natural · None lab-grown
- I3
- Not stocked
| Grade | Category | What it means |
|---|---|---|
| FL / IF | Flawless / Internally Flawless | No inclusions visible to a skilled grader at 10x. FL shows no blemishes either; IF may show minor surface blemishes. |
| VVS1 / VVS2 | Very, Very Slightly Included | Inclusions so slight they are extremely difficult for a skilled grader to find at 10x. |
| VS1 / VS2 | Very Slightly Included | Minor inclusions, difficult to somewhat easy to see at 10x. Almost never visible to the eye. |
| SI1 / SI2 | Slightly Included | Inclusions noticeable at 10x. Sometimes visible to the eye, more often in SI2 and in larger stones. |
| I1 / I2 / I3 | Included | Inclusions obvious at 10x and usually to the eye. They can affect transparency, brilliance and, at I3, durability. |
Eye-clean vs. graded clarity
A clarity grade describes a stone at 10x. Eye-clean describes it as you will actually see it: no inclusion visible without magnification, at a normal viewing distance.
VS2 and above are almost always eye-clean. Many SI1 stones are, and some SI2 stones, depending on the stone's size, its shape and where the inclusions sit. Eye-clean is not printed on any report; it is judged stone by stone.
Clarity grade and price
Price falls significantly as you move down the scale, and the top grades carry the steepest premium for differences no one sees without a loupe.
VS2 to SI1 is often where value sits: usually eye-clean, at a clear saving on the VVS grades above.
Natural and lab-grown
Lab-grown diamonds are more often available at VVS and above, at a price close to a natural stone several grades lower. The grade means the same thing on either; origin, not material, is the difference.
- FL
- IF
- VVS1
- VVS2
- VS1
- VS2 (usual value range)
- SI1 (usual value range)
- SI2
- I1
- I2
- I3
VS2 to SI1: usually eye-clean, and the usual balance of price and appearance.
How clarity interacts with the other Cs
Size matters: an inclusion is easier to see in a larger stone, where the facets that frame it are larger too. Shape matters more. Step cuts have long, open facets that show what is inside; brilliant cuts break the view into small flashes that hide it.
A well-cut stone's brilliance helps mask minor inclusions, and a prong or bezel placed over an inclusion near the edge can hide it entirely.
- Clarity
- FL to I2 on our listings; the full scale runs to I3.
- Colour
- D to Z for white diamonds, or a fancy-colour description.
- Cut
- How the proportions return light. Graded for round brilliants only.
- Polish
- The finish of the facet surfaces.
- Symmetry
- How precisely the facets align with each other and the outline.
Clarity by shape
Step cuts
Step cuts show inclusions
Long, open facets act like windows. Choose a higher clarity, and read the plot.
Brilliant cuts
Brilliant cuts hide them
Many small facets break up the view. A lower clarity is often invisible face up.
Choosing the right clarity grade
Aim for eye-clean
Buy a stone that looks clean to you rather than chasing the highest grade. The money is better spent on cut or size.
Brilliant shapes
Round, oval, pear and the other brilliants — and mixed cuts such as cushion and radiant — hide inclusions well. A lower clarity is usually safe.
Step-cut shapes
Emerald and asscher show inclusions through their open facets. Move up the scale, and look closely at the plot.
Ask for the plot
The inclusion plot on the report shows exactly what is in the stone and where. Ask for it, with images, before committing.
Read the grades together
Compare clarity alongside Colour, Cut, Polish and Symmetry, as our listings present them, not in isolation.
Frequently Asked Questions
What buyers ask most often about clarity before choosing a stone.
See how clarity trades off against the other Cs in the 4Cs calculator.
What clarity grade is 'eye-clean'?
Eye-clean is not a laboratory grade. It means no inclusion is visible without magnification at a normal viewing distance. VS2 and above are almost always eye-clean; many SI1 stones are, and some SI2 stones. It depends on the stone's size, its shape and where the inclusions sit, so it is judged stone by stone.
Is VVS clarity worth the extra cost?
Rarely for how the stone looks. VVS inclusions are extremely hard to find even at 10x, and a VS or eye-clean SI stone looks the same to the eye. VVS is worth paying for when rarity matters to you, in large step cuts, or where lab-grown makes the higher grade affordable.
Do inclusions affect a diamond's durability?
Usually not. Most inclusions are tiny and deep inside the stone. The exceptions are large feathers that reach the surface, especially near a girdle, point or corner, which can weaken the stone under a hard knock. They are most common in the I grades and worth checking on the plot.
What's the difference between an inclusion and a blemish?
An inclusion is inside the stone: a crystal, a feather, a pinpoint or a cloud. A blemish is on the surface: a polish line, a nick, a scratch or an extra facet. Both count towards the clarity grade, but inclusions usually decide it.
Do GIA and IGI grade clarity the same way?
Both grade on the same FL to I3 scale, under 10x magnification, and the grade names mean the same thing on either report. How strictly each laboratory applies the scale is debated in the trade, so read any single grade as a starting point and look at the plot and the stone.
Shop Diamonds by Clarity
Choose a grade, and a shape if you have one in mind, to open the catalogue already filtered. If nothing in stock fits, enquire and we will source to the specification.