Cutting of diamonds

Each diamond polisher needs to analyse the rough stone to the best of his knowledge and choose the appropriate way how he will polish the stone to get the best result possible. This is determined firstly by the shape of the and secondly by the inclusions in the rough diamond. Every cutter will try to maximize the final size of the polished diamond.

The process of cutting and polishing diamonds has largely remained unchanged since the invention of diamond polishing in the 14th century. Before polishing was invented the diamond was cherished and praised for its hardness and surface reflection of light. Since the invention of diamond polishing, we have discovered that the light breakage and internal reflection creates the brilliance which is the main attraction of diamonds today.

The first part in the polishing process is the planning and scanning of the rough diamond by one of the multiple diamond scanning technologies available on the market. After mapping all the inclusions and 3D modelling the potential result the diamond will usually be marked.

The next step will be to saw the diamond by a copper blade set with diamond powder and oil. It is the diamond powder that will actually cut the diamond as diamond is the only material that can cut diamonds. This sawing technique can also be done by laser cutting, a recently developed technique that is more accurate than sawing. This first cut usually sets where the table facet will be placed. Sawing or laser cutting is favoured over immediate polishing because a part of the diamond can be saved instead of turning it to diamond dust by polishing it off from the rough. In diamonds every point counts!

Once the diamond has been sawn the stone will be polished in a basic round shape, this is called blocking, usually by the time this process has been finished the diamond will have 17 or 18 facets. This is the first major transformation from rough to polished. Once the blocking is done you can already identify the future polished diamond’s shape and size. During blocking the majority of the weight loss of polishing will happen.

The last step is called brillianteering. This is the final stage of the cutting process, here the final facets are being polished and shaped to perfect proportions. This is the step that carries the most importance to create the brilliance and fire in the diamond.

Diamond polishing is a timely process, certain unique diamonds take years to polish as every step of the way is being checked and rechecked dozens of times. Once a part of the diamond has been removed it is gone forever. During the polishing process more than 50% of the weight of the rough diamond will be lost. If you would like to polish a 1ct diamond you will need a rough stone of at least 2.25ct.