What the grades mean
FL and IF are rare. VVS and VS grades usually carry clean appearance. SI can be good value if the inclusion is not visible to the naked eye and not in a risky position.
Why position matters
A small inclusion under a prong is different from a dark crystal in the table. A feather near the girdle can carry different risk from a pinpoint off to the side.
Selling clarity
When selling, clarity is not negotiated from memory. A certificate, plotted diagram, inscription, and physical inspection protect both seller and buyer.
How a grader settles the grade
GIA looks at five things for every inclusion: its size, how many there are, where it sits, what it is, and how much it stands out against the stone (its colour or relief). A small dark crystal under the table can pull the grade down further than a larger pale feather near the edge, which is why two stones with the same letter can look different.
Eleven grades, six groups
Flawless, Internally Flawless, VVS1 and VVS2, VS1 and VS2, SI1 and SI2, and I1, I2 and I3. Every grade is set at 10x magnification by a trained grader, so the letters describe what a loupe shows, not what you see across a table.
Decision table
Use the details, not a shortcut.
| Grade band | Plain-English read | Buyer note |
|---|---|---|
| FL/IF | No visible inclusions under grading conditions | Rare, premium priced |
| VVS1/VVS2 | Very difficult to see at 10x | High quality, often overkill for budget buyers |
| VS1/VS2 | Minor inclusions at 10x | Strong value band for many natural diamonds |
| SI1/SI2 | Noticeable at 10x, sometimes eye-visible | Inspect stone, not only grade |
| I1-I3 | Eye-visible inclusions | Price and durability need careful review |
Direct answers
Common questions
What does eye-clean mean?
It means inclusions are not obvious to the unaided eye in normal viewing. The term is practical, not a formal lab grade.
Is SI clarity always bad?
No. Some SI stones are attractive and fairly priced. Others have obvious or risky inclusions. Inspection matters.
What are VVS diamonds?
VVS means Very, Very Slightly Included. GIA describes the inclusions in VVS1 and VVS2 stones as difficult for a skilled grader to see even at 10x, so nothing shows to the naked eye. Only FL and IF rank higher, and for looks alone an eye-clean VS or SI stone is usually indistinguishable once set.
Can Prodiam value a diamond without a certificate?
Prodiam can inspect stones, but a recognised grading report usually makes pricing and resale discussions cleaner.