Diamond Cutting and Polishing

Rough diamonds

The rough diamond is sourced predominantly from South African mines (diamonds from other regions are also available) and sent to the diamond cutting and polishing factory for analysis. Diamonds 27 is committed to sourcing conflict-free diamonds from legitimate diamond sources who share our ethical philosophy and zero-tolerance policy towards conflict diamonds. Conflict-free diamonds refer to diamonds that are mined legitimately and ethically, in areas of the world that are free from violence and civil wars associated with or funded by the sale of diamonds.


Planning and analysing is a crucial step in diamond cutting and polishing because during this stage the size and relative value of the cut stones that the rough will produce are determined. The diamond is analysed according to its shape and qualities. The best shape for the diamond is then determined, and cut and polished accordingly. The planner must consider the size, clarity and crystal direction when deciding where to mark the diamond rough. Incorrectly marking a diamond by a fraction of a millimetre can make a huge difference to the diamond. In addition, if the diamond is cleaved in the attempts to wrong position, the diamond could shatter and become worthless.


After the diamond has been analysed and examined, the inclusions are noted and the yield of rough is determined. A diamond marker may decide to mark two or three diamonds from one piece of rough depending on the characteristics and inclusions present in the diamond. It may make more sense to polish two diamonds from a large rough around an inclusion to yield two smaller stones with a higher clarity, as opposed to one larger stone with a low clarity grade. Using the latest 3D laser scanning technology, the rough diamond is marked to guide the diamond cutter.


The marked diamond is placed on a jewellers sawing spindle. The blade is made from copper with a mixture of oil and diamond powder. The rough diamond is cut where it has been marked.  It is the diamond powder that physically cuts the diamond, not the copper blade. The reason for this is diamonds are the hardest known mineral to man, and only a diamond will cut another diamond.


This step lays the foundation for the potential of the diamond's performance because it establishes the diamond's basic symmetry. During the blocking stage, the first 17 or 18 facets are made, creating a single cut. For some very small diamonds, the process stops here. Larger diamonds go on to the brillianteering stage. In this process a specialist called a brillianteer, polishes the final facets. It is this stage that will determine how much brilliance and fire a diamond displays.


Polishing, also known as brillianteering, is the final stage of the cutting process. The diamond’s facets are polished and shaped to ideal proportions and perfect symmetry. Polishing is the name given to process whereby the facets are cut onto the diamond and final polishing is performed to shape the diamond to ideal proportions and perfect symmetry. This stage determines how much fire, brilliance and scintillation the diamond will have.