The gemstone measurements can be articulated in millimetres to two decimal places. The gemstone measurements can be applied; Round Shape: Depth and min, max diameter. Other Shapes: Depth and length, width. Diameter - mm Weight - ct 2.2 0.04 3.0 0.10 4.1 0.25 5.2 0.50 6.5 1.00 7.4 1.50 8.2 2.00 9.0 2.50 9.3 3.00 11.0 5.00