How to calculate a diamond carat weight?
There is a technique for weight calculation of fixed inserts by linear dimensions without attaching them.
In this case, the insert standard weight is firstly determined basing on its linear dimensions and using a coefficient depending on the shape of the insert.
To obtain a more accurate result, there are corrections for the thickness of the girdle, for breaking the symmetry of the cut, for convexity of the crown and pavilion, which are introduced in the calculation.
The satisfactory accuracy of weight measurement, taking into account all the corrections, is determined within ± 5%. However, it is necessary to take in mind the possible error in measuring the dimensions depending on the degree of availability of the insert in the product for use by the measuring instrument, and also the openness of the insert to the visual survey which makes it possible to evaluate the factors affecting the shape and symmetry of the weight. Thus, the satisfactory accuracy of the weight measurements for an inaccessible insert can be at ± 15%.