The length measures 7.42 millimeters, and the width measures 3.61 millimeters. 7.42 divided by 3.61 equals 2.056. The length to width ratio is expressed as 2.06:1.
In the elongated shapes, a length-to-width ratio (L/W) must be determined to complete this particular weight estimation formula. Here the L/W ratio is obtained by simply dividing the length of the stone by its (greatest) width.
Example: A marquis measures 10.83 mm long with a 4.97 mm width. 10.83 divided by 4.97=2.179 — rounded to 2.18. The length is 2.18 times the diameter of the width. The L/W ratio is expressed as 2.18 to 1 or 2.18:1. (The width will always be expressed as one in the ratio.)