Face-up size is how large a stone looks from above for its weight. Two stones of the same carat weight can differ in face-up size because of their depth and shape.
In more detail
A deep stone keeps more weight below the girdle, where it adds nothing to the face-up outline. A less dense material also faces up larger at the same weight. A 1.00 ct T73 is 6.48 mm across in diamond and 6.67 mm in moissanite.
How we measure it
Our gemstone cut pages measure face-up size per carat from each model's outline. The Spread score on the Cut Performance Wheel is a separate estimate, from depth alone.
Related terms
- Spread (light performance): Spread is an estimate of a cut's face-up size for its weight, compared with a stone 61.5% deep. Above 100 means the cut faces up larger for its weight than that reference.
- Specific gravity: Specific gravity compares a stone's weight with the weight of the same volume of water. It decides how much a stone of a given size weighs.
- Carat weight: Carat weight is the weight of a gemstone. One carat is 200 milligrams, a fifth of a gram, and it has 100 points.
- Total depth: Total depth is the height of a stone from table to culet as a percentage of its average diameter. It equals crown height + girdle thickness + pavilion depth.