Colour grading process and system for diamonds

A process operable using a computerized system for grading the colour of a diamond, wherein the colour of the diamond is correlated with the colour of a diamond of a plurality of diamonds each having a colour grading assigned thereto, the computerized system including an optical image acquisition device, a processor module and an output module operably interconnected together, said process including the steps of:

• (i) acquiring via an optical image acquisition device at least one first optical image of a table of a diamond, wherein the at least one first optical image is acquired at a predetermined angle with respect to a central axis extending normal to the table and through an apex of a pavilion of the diamond and in a direction of towards the table and wherein the at least one first optical image is acquired in an environment having a predetermined constant light level;
• (ii) in a processor module comparing data derived from acquisition of the at least one first optical image with a plurality of data sets each of which corresponds to a diamond of a plurality of diamonds, wherein the plurality of data sets are each derived from an optical image of the table of the plurality of diamonds acquired by an optical image acquisition device in an environment having a predetermined constant light level the same as the predetermined constant light level used in acquiring the at least one first optical image and each of the plurality of data sets is assigned a colour grading, and wherein said data derived from acquisition of the at least one first optical image and the data of said plurality of data sets are data indicative of the colour of the diamond from which it is acquired;
• and
• (iii) from an output module, responsive to a predetermined threshold of correlation existing between the data derived from acquisition of the at least one first optical image and data derived from one of the plurality of data sets, generating an output signal indicative of the colour grade of the diamond.