FANCY STONE GRADING
Then you measure the stone’s dimensions-width, length, and depth-in millimeters, interpolating to the nearest 0.01 mm.
Width in round stones means diameter: it is the average of the minimum and maximum girdle diameters. In square stones width is the average of the two side-to-side measurements.
On rectangular shapes, length is the distance from end to end measured along the longest side (not diagonally). Width is the distance between (and at right angles to) the longest sides.
With most other fancy cuts, length is the longest dimension, and width is the widest dimension perpendicular to the length.
On hearts, however, width is the measurement between the widest parts of the lobes, while length is the perpendicular distance from the point to an imaginary line across the top of the lobes.
And on triangles, width is the distance from corner to corner on the shortest or longest side (if all are equal, any side), while length is the perpendicular distance from the center of the width side to the opposite point.
These diagrams show where you measure the length and width of different fancy shapes.