Every diamond is unique, but every cut diamond is built from the same basic parts. How those parts are proportioned decides how much light the stone returns, how large it looks and how much it sparkles. Here are the eight parts worth knowing.
What Is Diamond Anatomy?
Each shape has its own facet pattern, but all cut diamonds share the same sections. The size and angle of each section control how light travels through the stone. A cut grade sums this up in one word, and knowing the parts behind it helps you read a grading report and compare stones.
The Parts of a Diamond
Table
The table is the largest facet, the flat surface across the top of the diamond. Its size is given as a percentage of the diamond's width.
Crown
The crown is the angled upper section between the table and the girdle.
- Crown height: the distance from the girdle to the table.
- Crown angle: the angle of the crown facets. It has a strong effect on fire and on how light enters and leaves the stone.
Girdle
The girdle is the narrow band around the widest part of the diamond, where it sits in the setting. A very thick girdle adds weight without adding size. A very thin one can chip. A medium to slightly thick girdle is ideal.
Diameter
The diameter is the width of the diamond at the girdle, its widest point.
Pavilion
The pavilion is the lower section, from the girdle down to the point.
- Pavilion depth: if it is too shallow or too deep, light escapes through the bottom and sides instead of returning through the top.
- Pavilion angle: one of the main factors in a diamond's overall brightness.
Lower Half Facets
The lower half facets run from the girdle toward the point. Their length, measured as a share of the pavilion, affects contrast. Longer lower halves create a little more sparkle when the stone moves.
Culet
The culet is the tiny point, or very small facet, at the bottom of the diamond. In a modern cut it should be invisible to the eye. Large culets, common in older cuts, let light escape and can show as a small dark spot.
Total Depth
Total depth is the height of the diamond from the table to the culet, given as a percentage of its width.
Why Anatomy Matters
A diamond's fire, brilliance and sparkle come from how all these parts work together. That is what the cut grade measures, and why we suggest putting cut first. Read more in our guide to diamond cut.
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