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Formula For Diamond Calculations

Please take note of all the formulae presented in this section.  They are here for easy reference should you have to make any quick calculations once you are given the dimensions of the diamond.   Also, should you be given a detailed appraisal on a diamond by a jewellery store or by your own independent gemmologist you will know exactly what all the figures stated on the report mean.

The most important calculations involve the first two formulae, one for the depth percentage and the one for the table percentage.

 

1.  Depth Percentage
Total depth of the diamond in mms. as measured from the table to the culet.

_______(divided by)__________

Diameter of the diamond in mms.

 

2.  Table Percentage
Measurement in mms. of table from corner to corner

_______(divided by)__________

Diameter of diamond as measured from girdle edge to opposite girdle edge.

 

3.  Girdle Thickness Percentage
Thickness of the girdle in mms. where the pavilion main facets and bezel facets meet

_______(divided by)_________

Diameter of the diamond in mms.

 

4.  Pavilion Depth Percentage
Depth of the pavilion as measured from the culet to the girdle in mms.

_______(divided by)_________

Diameter of the diamond in mms.

 

5.  Crown Height Percentage
Height of the crown as measured in mms. from the girdle to the table

_______(divided by)_________

Diameter of the diamond in mms.

 

6.  Crown angle should ideally be 34.5 degrees.
7.  Pavilion angle should ideally be 41 degrees.