Diamond anatomy

💎 Diamond Anatomy: Understanding Each Facet of a Brilliant Cut

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, depending on whether the culet is faceted or pointed. Each part of the diamond plays a crucial role in its optical performance.

1. Table

• The largest flat facet on the top of the diamond.

• Allows light to enter and exit the diamond.

• Typically comprises 50–60% of the total diameter in ideal cuts.

• Impacts both brightness and the visibility of the diamond’s interior.

2. Crown

• The portion above the girdle, extending from the table to the girdle edge.

• Comprised of several key facet types:

  • 8 Star Facets – Triangular facets adjacent to the table.

  • 8 Bezel (or Kite) Facets – Kite-shaped, between star and upper girdle facets.

  • 16 Upper Girdle Facets – Located just above the girdle.

• The crown height and angle affect dispersion (fire) and light refraction.

3. Girdle

• The narrow band that separates the crown and pavilion.

• Can be:

  • Faceted (preferred for symmetry and reflection),

  • Polished, or

  • Bruted (matte finish, older styles).

• Girdle thickness is critical: too thin = prone to chipping; too thick = adds unnecessary weight.

4. 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 – Triangle-shaped, extend from girdle to culet.

  • 16 Lower Girdle Facets – Narrower facets between pavilion mains and girdle.

• Pavilion depth and angle are crucial to total internal reflection.

5. Culet

• The very bottom point of the pavilion.

• Can be:

  • Pointed (common in modern cuts),

  • Small Facet (in antique or certain modern cuts).

• A large culet appears as a visible dot when viewed through the table.

Key Optical Functions of Diamond Anatomy

• Brilliance: White light return, heavily influenced by the crown, pavilion, and table alignment.

• Fire: Color dispersion through crown facets.

• Scintillation: Sparkling effect caused by light/dark facet contrast during motion.

Facet Count Breakdown (Round Brilliant)