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