The anatomy of a diamond — particularly the modern round brilliant cut — is a result of precise proportions, geometry, and symmetry designed to maximize light return and visual brilliance. A standard round brilliant diamond features 57 or 58 facets.
Table
The largest flat facet on the top of the diamond. Allows light to enter and exit. Typically comprises 50–60% of the total diameter in ideal cuts.
Crown
The portion above the girdle, extending from the table to the girdle edge. Comprised of 8 Star Facets, 8 Bezel/Kite Facets, and 16 Upper Girdle Facets. Crown height and angle affect dispersion (fire) and light refraction.
Girdle
The narrow band separating the crown and pavilion. Can be faceted (preferred), polished, or bruted. Too thin = prone to chipping; too thick = adds unnecessary weight.
Pavilion
The lower section below the girdle, culminating at the culet. Responsible for reflecting light back through the crown. Composed of 8 Pavilion Main Facets and 16 Lower Girdle Facets.
Culet
The very bottom point of the pavilion. Can be pointed (modern cuts) or a small facet (antique cuts). A large culet appears as a visible dot through the table.
Key Optical Functions
- Brilliance: White light return, influenced by crown, pavilion, and table alignment.
- Fire: Color dispersion through crown facets.
- Scintillation: Sparkling effect from light/dark facet contrast during motion.
Facet Count (Round Brilliant)
| Facet Type | Count |
|---|---|
| Table | 1 |
| Star Facets | 8 |
| Bezel/Kite Facets | 8 |
| Upper Girdle Facets | 16 |
| Pavilion Facets | 8 |
| Lower Girdle Facets | 16 |
| Culet (optional) | 1 |
| Total | 57–58 |
