A process operable using a computerized system for grading the clarity of a diamond , the computerized system including an optical image acquisition device , a processor , a pre-trained neural network and an output module operably interconnected together, said process including the steps of: (i) acquiring via the optical image acquisition device one or more plurality of axial view images of a diamond with different focus depths, wherein the focal depths are determined by the height of the diamond and the plurality of axial view images are acquired in an environment having a predetermined constant light level, and wherein the axial view is defined as a view towards the diamond in a direction of a central axis normal to the table of the diamond and passing through the apex of the pavilion of the diamond , and the height of the diamond is defined as the length of the central axis of the diamond , (ii) in the processor , combining the plurality of axial views to form one or more single optical images, wherein the single image comprises in-focus defects from the plurality of axial views and wherein the single image is such that out of in-focus defects from the plurality of axial views within the diamond are rejected; (iii) in the pre-trained neural network , providing a continuous regressive value of a regression associated with the clarity grade of said diamond based on the one or more single images acquired during step (i); wherein the pre-trained neural network has been pre-trained utilising one or more single optical images acquired from a plurality of diamonds each having a pre-assigned clarity grade assigned thereto and wherein the one or more single optical images acquired from a plurality of diamonds are provided by the same process of step (i), and are acquired in an environment having a predetermined constant light level the same as that as in step (i); and (iv) providing by the output module a clarity grade to the diamond of step (i) by correlating the continuous regression value from step (iii) to a clarity grade (i) acquiring via the optical image acquisition device one or more plurality of axial view images of a diamond with different focus depths, wherein the focal depths are determined by the height of the diamond and the plurality of axial view images are acquired in an environment having a predetermined constant light level, and wherein the axial view is defined as a view towards the diamond in a direction of a central axis normal to the table of the diamond and passing through the apex of the pavilion of the diamond , and the height of the diamond is defined as the length of the central axis of the diamond , (ii) in the processor , combining the plurality of axial views to form one or more single optical images, wherein the single image comprises in-focus defects from the plurality of axial views and wherein the single image is such that out of in-focus defects from the plurality of axial views within the diamond are rejected; (iii) in the pre-trained neural network , providing a continuous regressive value of a regression associated with the clarity grade of said diamond based on the one or more single images acquired during step (i); wherein the pre-trained neural network has been pre-trained utilising one or more single optical images acquired from a plurality of diamonds each having a pre-assigned clarity grade assigned thereto and wherein the one or more single optical images acquired from a plurality of diamonds are provided by the same process of step (i), and are acquired in an environment having a predetermined constant light level the same as that as in step (i); and (iv) providing by the output module a clarity grade to the diamond of step (i) by correlating the continuous regression value from step (iii) to a clarity grade <EOS>