Clarity describes the tiny characteristics inside a diamond, called inclusions, and on its surface, called blemishes. Almost every diamond has them: they are part of how the crystal grew. Clarity grading describes how visible they are under 10x magnification.
The clarity scale
| Grade | Name | What it means |
|---|---|---|
| FL | Flawless | No inclusions or blemishes visible under 10x |
| IF | Internally Flawless | No inclusions; only minor surface blemishes under 10x |
| VVS1, VVS2 | Very, very slightly included | Inclusions extremely difficult to see under 10x |
| VS1, VS2 | Very slightly included | Minor inclusions, difficult to somewhat easy to see under 10x |
| SI1, SI2 | Slightly included | Inclusions noticeable under 10x |
| I1, I2, I3 | Included | Inclusions obvious under 10x; may be visible to the eye and may affect durability |
What graders consider
Size, number, position, nature and relief (how much an inclusion contrasts with the diamond). A small inclusion under the table is more visible than a larger one near the edge, where it may be hidden by a prong.
Eye-clean
A diamond is called eye-clean when no inclusions can be seen without magnification at a normal viewing distance. It is not an official grade, but it is often the most useful target: paying for a higher clarity grade makes no visible difference once a stone is eye-clean.
Shape matters
Brilliant cuts, such as round and oval, hide inclusions well because their facets scatter light. Step cuts, such as emerald and asscher, have broad, open facets that reveal them. For step cuts, a higher clarity grade is often worth considering.
Clarity treatments
Some diamonds are treated to improve their apparent clarity, for example by laser drilling or by filling fractures with a glass-like material. Treatments must be disclosed. Fracture filling can be damaged by heat or harsh cleaning, and some laboratories do not issue grading reports for fracture-filled diamonds.
Common types of inclusions
| Inclusion | What it looks like |
|---|---|
| Crystal | A small mineral crystal trapped inside the diamond |
| Feather | A small internal break, white or transparent |
| Cloud | A group of tiny pinpoints that can look hazy |
| Pinpoint | A very small dot, usually white |
| Needle | A long, thin crystal |
| Knot, cavity, chip | Features that reach the surface |
Clarity and durability
Most inclusions do not affect durability. Exceptions are large feathers, especially near the girdle or reaching the surface, which can make a diamond more vulnerable to chipping if struck. This is one reason to pay attention to the position of inclusions, not only to the grade.
Choosing clarity by shape and size
- Round and other brilliant cuts, under about one carat: VS2 or SI1 stones are often eye-clean; check each stone.
- Larger brilliant cuts: inclusions are bigger in absolute terms, so higher grades are worth considering.
- Step cuts: VS grades or higher are often preferred because the open facets reveal inclusions.
Laboratory-grown diamonds
Laboratory-grown diamonds are graded on the same scale. Their inclusions can differ from natural ones, but the grade describes their visibility in the same way.
Sources: Gemological Institute of America (gia.edu), the 4Cs of diamond quality and GIA grading scales.
Frequently asked questions
What clarity grade is eye-clean?
It depends on the stone. Many VS diamonds and some SI diamonds show no inclusions visible to the unaided eye, especially in brilliant cuts.
Does clarity affect sparkle?
Usually only at the lower grades, where large or numerous inclusions can reduce brilliance or durability.
Is a flawless diamond worth it?
Flawless diamonds are rare and priced accordingly. Once a diamond is eye-clean, a higher clarity grade does not change how it looks when worn.
Can inclusions be removed?
Treatments such as laser drilling can reduce the visibility of some inclusions. They must be disclosed.
