Translating the Technical Jargon on Your Grading Report

Table, Crown, Girdle, and Culet. Decode the architectural blueprint of your diamond and learn how to spot hidden red flags.

If you look closely at a GIA or IGI diamond certificate, you will find a small, highly technical diagram that looks like an architectural blueprint. It maps out the exact proportions of the stone, labeled with terms like Table, Depth, Girdle, and Culet.

While the overall "Cut Grade" gives you a general idea of the diamond's quality, understanding the actual anatomy of the stone empowers you to separate a "good" diamond from an absolute masterpiece. At KESONLY, we analyze these micro-measurements so you don't have to, but we love educating our clients on what we look for. Let’s decode the anatomy of a diamond.

1. The Table (The Window)

The Table is the large, flat facet on the very top of the diamond. Think of it as the main window into the stone.

• Its Job: It allows light to enter the diamond and travel down into the core.
• The Trap: You might think, "Bigger window = more light, right?" Wrong. If the table percentage is too large, the diamond won't have enough upper-side facets (the Crown) to create colorful rainbow fire. If the table is too small, the diamond won't look brilliant. Balance is everything.

2. The Crown and Pavilion (The Mirrors)

The Crown is the upper half of the diamond (above the belt), sloping down from the table. The Pavilion is the lower, V-shaped half (below the belt).

• Their Job: Once light enters through the Table, it hits the Pavilion facets, which act as mirrors to bounce the light perfectly back up through the Crown to your eye.
• The Trap: If the Pavilion is cut too deep, light leaks out the bottom, creating a dark, dead center. If it is cut too shallow, the diamond looks glassy and loses its sparkle.

3. The Girdle (The Belt & The Danger Zone)

The Girdle is the outer edge or "belt" that separates the Crown (top) from the Pavilion (bottom). This is the part of the diamond that the metal prongs of your ring will actually grip.

4. The Culet (The "Black Hole" Effect)

The Culet (pronounced kyoo-lit) is the tiny point at the very bottom tip of the diamond.

In antique diamonds (like Old European Cuts), the culet was literally sliced off, leaving a small flat facet at the bottom. However, in modern Round Brilliant cuts, the culet should be a sharp, closed point.

The Golden Rule: On your grading report, you always want the Culet to be graded as "None" or "Pointed." If a modern diamond has a "Large" culet, you will be able to look straight down through the top of the diamond and see a dark circle—it looks like a black hole or a piece of dirt trapped inside the stone!