Measurements is the report line that gives a stone's size in millimeters. A round reads minimum – maximum diameter × depth, and a fancy shape length × width × depth.
In more detail
One cut in one material has only one size at a given weight, so weight and measurements check each other. In our simulator, a 1.00 ct T73 is 6.48 mm across in diamond and 6.67 mm in moissanite. Divide the depth by the average diameter to get the total depth percentage. A big gap between the two diameters shows a round that is out of round.
On a grading report
In the identity block of every GIA and IGI diamond report.
Related terms
- Average diameter: The average diameter of a round is the mean of its minimum and maximum diameters, measured across the girdle.
- 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.
- 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.
- Length-to-width ratio: The length-to-width ratio of a fancy shape is its length divided by its width, both taken from the measurements.
- Moissanite: Moissanite is silicon carbide, one silicon atom for every carbon atom, in a hexagonal crystal. It is a diamond simulant, and every moissanite in jewelry is laboratory-grown.