Culet
The point — or tiny protective facet — at the very bottom of a diamond's pavilion. Modern stones have None or Very Small; a large culet reads as a dark circle through the table.
Every diamond has a bottom. In a modern round brilliant, the eight pavilion main facets converge to a sharp point — graded "None" — or a microscopic flat facet called the culet. The culet exists to protect the tip from chipping, which was a real risk when diamonds were set by hand with crude tools.
Today's precision setting techniques make a large culet unnecessary. A None or Very Small culet is standard in modern cuts. The issue arises with older stones: antique Old Mine and Old European cuts were routinely finished with large culets as a protective measure, and they are clearly visible as circles when looking down through the table.
The GIA grades culets on an eight-point scale from None to Extremely Large. For a modern round brilliant to receive an Excellent cut grade, the culet must be None, Very Small, Small, or Medium. Anything larger rules out the top grade.
- LOCATION
- Pavilion tip
- IDEAL SIZE
- None / Very Small
- GIA EX CUTOFF
- ≤ Medium
The pavilion facets meet at a perfect point with no additional facet. The ideal for most modern cuts — no visual artefact from above.
A tiny facet, typically under 0.5% of the average girdle diameter. Essentially invisible to the naked eye and has no impact on appearance or value.
Still small enough to be imperceptible without magnification. Common in older precision cuts and some fancy shapes. Included in GIA Excellent cut grade range.
Visible under 10× loupe. May be barely perceptible face-up in very clear stones. Acceptable but not ideal — many buyers prefer None or Very Small.
Clearly visible as a small circle through the table without magnification, especially in VS+ clarity stones. Creates the impression of an inclusion at the centre of the stone.
Common in antique Old Mine and Old European cuts. The circle is prominent from above and dramatically reduces the stone's apparent clarity. Acceptable in antique cuts where it is part of the period aesthetic.
GIA culet size scale
GIA grades culets on eight levels. The face-up effect column describes what you actually see when looking straight down through the table at normal viewing distance (≈ 25 cm).
Modern vs antique culets
The culet tells a story about when and how a diamond was cut.
None or Very Small
- Round brilliant, oval, cushion, princess: None or Very Small standard
- GIA Excellent cut grade requires ≤ Medium
- Modern setting tools can grip the girdle without stressing the tip
- No visual artefact — uninterrupted brilliance pattern face-up
- Slightly protective: Very Small guards against chipping during setting
- Price: no impact vs. None
Medium to Extremely Large
- Old Mine (pre-1900) and Old European (1890s–1930s): culets were standard
- Protected tips from chipping during hand-setting with early prong tools
- Creates distinctive "bull's-eye" view from above — part of antique character
- Not a defect in context — expected by collectors of antique diamonds
- If re-cutting is considered, the culet can be removed — but this loses carat weight
- Document and disclose when reselling antique stones
How the culet affects appearance
A diamond's pavilion is designed as a mirror system: the angled facets reflect light back up toward the observer's eye. A sharp culet point contributes to this system because it is just another facet edge — too small to interrupt the pattern.
A large flat culet breaks the mirror system at the centre. Instead of reflecting, it transmits light downward — appearing dark. Because the culet sits at the exact optical centre of the stone, this dark spot is visible through the table and through the table reflections in the bezel facets. It multiplies. In high-clarity stones where there is nothing else competing for attention, it can look startlingly like an inclusion.
In lower-clarity stones with visible inclusions, a medium culet may disappear visually among the other characteristics. But in a VS2 or better stone, even a Medium culet may be noticeable to a careful observer.
Effect on clarity grade
The culet is not classified as an inclusion — it is a cut characteristic. GIA does not penalise clarity for culet size. However, a large culet is called out separately in the "Additional Grading Information" section of the report and will appear in the plotting diagram.
Effect on cut grade
For round brilliants, GIA's cut grade model caps at Excellent for culets up to Medium. Slightly Large culets drop the cut grade to Very Good at best. Large or Very Large culets can result in a Good or lower cut grade, regardless of other proportions.
Effect on value
A Large culet on a modern brilliant will be reflected in price — buyers discount stones with visible face-up artefacts. None vs Very Small carries no price difference. For antique stones, a large culet is expected and priced accordingly by the market.
Questions about the culet
What is a culet and where is it?
The culet is the very bottom point of a diamond — the tip of the pavilion. In modern cuts it is either a sharp point (graded "None") or a tiny flat facet. In antique cuts like Old Mine and Old European, it was deliberately left as a larger facet to protect the stone from chipping during setting, when tools were cruder.
Why does a large culet appear as a dark circle?
When you look straight down through a diamond's table, a large culet acts like a tiny window through which you can see the back of the stone. Instead of reflecting light back toward your eye (as the sharp pavilion facets do), it lets light escape downward, creating a dark or grey circle at the center of the stone. The larger the culet, the more prominent the circle.
What culet size should I look for?
For modern cuts — round brilliants, ovals, cushions, princess — look for None or Very Small. Small is acceptable and has no visible effect. Medium is borderline; it may be perceptible face-up in higher clarity stones. Large and Very Large significantly detract from appearance and should be avoided unless you are deliberately buying an antique-style stone where a larger culet is part of the character.
Does the culet show up on a grading report?
Yes. GIA, IGI, and AGS reports all list culet size as part of the proportions section, graded on the scale: None, Very Small, Small, Medium, Slightly Large, Large, Very Large, Extremely Large. The GIA Excellent cut grade for round brilliants permits culet sizes up to Medium. For fancy shapes, GIA reports show culet but do not assign a formal cut grade.
Is a None culet better than Very Small?
In practice they are identical. Both are invisible face-up and have no effect on appearance, light performance, or price. "None" simply means the facets meet at a perfect geometric point. "Very Small" means there is a tiny protective facet — historically useful when setting diamonds by hand. Either grade is ideal for a modern stone.
Do antique diamonds always have large culets?
Old Mine cuts (pre-1900) and Old European cuts (1890s–1930s) typically have Medium to Very Large culets — it was standard practice and a defining feature of those styles. When evaluating antique diamonds, a large culet is expected and does not carry the same negative connotation as in a modern brilliant. Many buyers specifically appreciate the "bull's-eye" look of an antique culet as part of the stone's period character.