Here are some useful formulas for estimating the weight of stones in settings, where the stones cannot be removed for accurate weighing. All weights are given in carats, and all measurements in millimeters. Dimensions should be measured as accurately as possible using a precision gauge (such as the Leveridge gauge displayed here). An asterisk (*) indicates multiplication; slash (/) indicates division. S.G. stands for specific gravity (see individual stone descriptions for values). These formulas are calculated for well proportioned stones; add 2% to 6% for bulge factor, i.e., excessively steep crown or pavilion angles. The resulting weights are approximate estimates only, and it will take a bit of practice at estimating bulge factors to improve accuracy.