Crown
The upper portion of a diamond, from the girdle up to the table. Crown angle and height are two of the most critical cut measurements for fire and brilliance.
A diamond has three main zones: the crown (top), girdle (equator), and pavilion (bottom). The crown faces upward and is the part of the stone visible when it is set in jewellery. In a standard round brilliant, the crown carries 33 of the stone's 58 facets.
Crown angle — the angle of the bezel facets relative to the girdle plane — is one of the most important single proportions in a diamond. It directly controls how much fire (spectral colour dispersion) the stone produces. GIA's ideal range for Excellent cut rounds is 34–35°.
Crown height percentage — how tall the crown is relative to girdle diameter — works alongside crown angle. Together they define the bezel facet geometry that makes the difference between a flat, glassy stone and one with vivid fire.
- LOCATION
- Above girdle
- IDEAL ANGLE
- 34–35°
- IDEAL HEIGHT
- 14–17%
Table
The large flat facet on the very top of the diamond. The primary window for light to enter and exit the stone. Table percentage (table width ÷ girdle diameter) is one of the key cut proportions.
Highlighted in blue in the cross-section above.
Star facets
Eight small triangular facets surrounding the table, pointing inward. They form the eight-pointed star pattern visible when looking straight down at a round brilliant.
Highlighted in blue in the cross-section above.
Bezel facets
Also called kite or main crown facets. Eight large kite-shaped facets that make up most of the crown surface. Their angle (the crown angle) is one of the most important cut measurements.
Highlighted in blue in the cross-section above.
Upper girdle facets
Sixteen small triangular facets at the bottom of the crown, adjacent to the girdle. They complete the crown and influence scintillation — the number of sparkle flashes when the stone moves.
Highlighted in blue in the cross-section above.
Crown facet anatomy
A standard round brilliant crown has 33 facets across four types. Each type plays a distinct optical role.
Table
Main light entry and exit point
The large flat facet on the very top of the diamond. The primary window for light to enter and exit the stone. Table percentage (table width ÷ girdle diameter) is one of the key cut proportions.
Star facets
Define the table border; affect fire
Eight small triangular facets surrounding the table, pointing inward. They form the eight-pointed star pattern visible when looking straight down at a round brilliant.
Bezel facets
Primary fire generators; largest crown facets
Also called kite or main crown facets. Eight large kite-shaped facets that make up most of the crown surface. Their angle (the crown angle) is one of the most important cut measurements.
Upper girdle facets
Scintillation and light break-up
Sixteen small triangular facets at the bottom of the crown, adjacent to the girdle. They complete the crown and influence scintillation — the number of sparkle flashes when the stone moves.
Total: 33 crown facets. Combined with 25 pavilion facets (8 main + 16 lower girdle + 1 culet) = 58 facets for a standard round brilliant.
Crown angle
Crown angle is the angle between the bezel (main crown) facets and the imaginary horizontal plane of the girdle. It is one of the seven measurements GIA uses in its cut grade model.
The crown angle primarily controls fire — the dispersion of white light into spectral colours. Steeper crown angles produce more fire. Shallower angles produce more brilliance (white light return). The sweet spot for Excellent cut round brilliants is 34–35°.
Crown angle interacts strongly with pavilion angle. The combination of 34–35° crown + 40.6–41° pavilion is widely considered the optimal pairing for round brilliants.
Too shallow
Reduced fire; glassy appearance
Acceptable
Good but not exceptional fire
Ideal (EX)
Maximum balance of fire and brilliance
Very good
Slightly more fire, marginally less brightness
Too steep
Reduced face-up size; can look darker
Crown vs Pavilion
The crown and pavilion work together. Neither can be evaluated in isolation.
Above the girdle
- Controls fire (spectral colour dispersion)
- Table is primary light entry and exit point
- Crown angle is key proportion (ideal: 34–35°)
- Crown height: typically 14–17% of girdle diameter
- Smaller table leaves more bezel area → more fire
- 33 facets in a standard round brilliant
Below the girdle
- Controls brilliance (white light return)
- Pavilion angle is the most critical cut measurement
- Pavilion angle ideal: 40.6–41° for round brilliants
- Pavilion depth: typically 42–44% of girdle diameter
- Acts as a mirror system — reflects light back up through crown
- 25 facets in a standard round brilliant
Questions about the crown
What is crown angle and why does it matter?
Crown angle is the angle between the bezel facets and the girdle plane, typically measured in degrees. GIA's ideal range for Excellent cut rounds is 34–35°. A steeper crown angle (higher number) produces more fire — rainbow flashes of colour. A shallower crown angle emphasises brilliance — white light return. The crown angle interacts with the pavilion angle: certain combinations produce dramatically more beautiful stones than others, which is why a single measurement is never enough.
What is crown height percentage?
Crown height % is the vertical distance from the girdle plane to the table, expressed as a percentage of average girdle diameter. Typical ideal range for round brilliants is 14–17%. A very low crown (under 10%) produces a flatter-looking stone that may appear glassy and have reduced fire. A very tall crown (over 20%) can look dramatic but affects proportions in ways that interact with pavilion depth.
How does the table percentage relate to the crown?
The table facet is the top of the crown, so table % and crown height % are directly related. A large table (over 60%) leaves less room for the bezel facets, reducing fire. A small table (under 52%) leaves more bezel facet area but can reduce overall brightness. The optimal balance for a round brilliant EX cut is a table of 54–57% with a crown height of around 15–16%.
Do all diamond shapes have the same crown facet arrangement?
No. The round brilliant's 33-facet crown (1 table + 8 star + 8 bezel + 16 upper girdle) is the standard, but fancy shapes use different arrangements. An emerald cut has a step-cut crown with long parallel facets and no star facets. A princess cut has a modified brilliant crown. Hearts, ovals and pears have brilliant-style crowns adapted to their outlines. Only round brilliants receive a formal cut grade from GIA that evaluates crown proportions.
Can I see crown proportions on a grading report?
Yes. GIA and IGI reports list crown angle and crown height % for round brilliants as part of the proportions diagram. For fancy shapes, GIA reports show total depth % and table % but not always crown and pavilion separately. Third-party analysis services like Sarine and OGI can produce full optical scan reports with detailed crown measurements for any shape.
What makes a crown too shallow or too deep?
A too-shallow crown (low crown angle, under ~30°) reduces the bezel facet area, limiting fire. The stone may look bright but flat — more like a window than a jewel. A too-deep crown (over ~38°) can make the stone look darker and reduce overall face-up size for a given carat weight, because more mass is above the girdle. The practical effect also depends on the pavilion — a deep crown can partly compensate for a shallow pavilion and vice versa.