Nevertheless, most of the rough diamonds from African mines are either sold in auctions or through supply contracts with miners. Until now almost 90% of the rough stones traded are cut and polished in Surat, India. The finished gems pass through traders in Antwerp, Belgium or in Dubai who supply them to the retail market. Thus, the average gem travels around the globe before it reaches the customer.
This inefficient distribution system is about to change. In a bid to increase their share of the value chain, African mining
countries have placed restrictions on the export of large carat stones. They are also investing in diamond polishing facilities
to export gems instead of stones. The major challenge facing these countries is that the traditional way of cutting and polishing diamonds requires specific manual skills.
In a conventional process, there are five steps for finishing a diamond: sorting the rough, planning for manufacturing, sawing the rough into a preliminary shape, shaping the girdle and polishing the facets. Each step is carried out in a separate production facility. It takes an average of a fortnight to convert a stone into a polished gem, but with all the middlemen, transport and customs, the entire process can take up to 6 months.
Once the rounded shape of the rough is formed (bruting), the most difficult operation is to form the facets of the diamond. The polisher places the rough on a rotating arm called tang and uses a spinning wheel to create reflective facets on the diamond. In the first operation, the polisher cuts eighteen facets. In the second operation, the remaining facets are added, bringing the total to 57 facets. The brilliance of the diamond is determined at this stage.
A well-cut diamond reflects and refracts light. These optics are due to careful polishing. The symmetry and proportions must be right to direct the maximum amount of light. The beauty of modern diamonds is thanks to the perfection of the diamond polisher’s art.
To replace the need for such polishing skills, mining countries are relying on technology. The new generation machines use lasers and 5-axis-CNC technology to replace the skilled labour needed for cutting and polishing diamond stones. The only fully automated laser solution is Synova’s DaVinci Diamond Factory®. This laser machine combines three operations: cutting, bruting and faceting.