The Anatomy of a Diamond, in Plain English

Table, crown, girdle, pavilion, culet. The five words that let you discuss a diamond properly, and why the girdle matters most on a marquise.

Five words. Learn them and you can hold a conversation with any jeweller in the world without nodding along to something you did not follow.

The map

Table, the large flat facet on top. The main window light enters through.

Crown, the sloped section between the table and the widest point.

Girdle, the widest part, the outline of the stone. This is where a diamond is usually gripped by its setting.

Pavilion, the cone beneath the girdle, running down to the point.

Culet, the very bottom. On many modern stones it is a point rather than a facet.

Why the proportions matter

Light enters through the table, travels down into the pavilion, reflects off the internal surfaces and returns to your eye. If the pavilion is too deep or too shallow, light escapes through the bottom instead of coming back. The stone looks dull or glassy at the centre.

This is what cut quality is measuring. Not shape, geometry.

The one that matters on a marquise

The girdle.

On a marquise the girdle narrows to a point at both ends, and at those points it is extremely thin. A girdle that is too thin at the tips is fragile, it chips. A girdle that is too thick adds weight you paid for but cannot see, because the extra material is buried inside the setting.

When we set a marquise, both points are covered by prongs. Not for decoration. Because that is where the stone is vulnerable.

The practical use of all this

Next time you look at a stone, look at it from the side rather than face-up.

Almost nobody does, and the side profile tells you most of what the face-up view is hiding.

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C'Garden is an independent bespoke jeweller in Kuala Lumpur. We are not affiliated with, endorsed by, sponsored by or certified by any organisation, laboratory or brand named in this article. Third-party names are used only to refer factually to those organisations and their published standards. All text and imagery in this article is original work created by C'Garden.

Reference

Gemological Institute of America. (n.d.). Anatomy of a diamond. GIA 4Cs. https://4cs.gia.edu/interactive-4cs/cut/anatomy.html