HOW TO CUT A ROUGH DIAMOND?
In this guide, you will learn what really happens behind the scenes, from the rough diamond to the shining diamond and sparkling.
Did you know that nearly 80% of all rough diamonds pass through various hands in the city of Antwerp, Belgium? Of these rough stones that are traded, 92% end up in India and are actually cut in the city of Surat.
This means that the diamond you buy on the market today has more than likely traveled around the world before it arrives in your hands!
How are diamonds cut and polished from rough diamonds?
Cutting a diamond is a process that involves transforming a diamond from its raw state to bring out a beautiful gemstone shape.
The process must be undertaken by a professional with the knowledge, equipment, and tools necessary for this work, as each decision made will have an impact on the result obtained at the end.
So what are the main considerations a cutter takes into account when considering cutting a diamond?
The first choice to make is to decide on the shape elle itself that one wishes to obtain: round diamond, oval, pear, princess, radiant, cushion... Then, the proportion of facets and the quality of the cut (i.e. symmetry and polishing) are planned using computer simulations.
The process of cutting and polishing diamonds
As diamond is the hardest material in the world, only a diamond can be used to mechanically cut another diamond. Lasers are another alternative, but their use is largely limited to cleaving and cutting. Usually, the tools used in the workshop are either diamond blades or discs that are coated with diamond dust. The process of cutting and polishing diamonds can be broken down into five steps:
- Planning,
- Cleaving,
- Roughing,
- Polishing and shining.
1. Planning the size of a rough diamond
Planning the size of a rough stone is one of the most important things to do. Although this process may take time, it is also the step that determines the final value of the finished products.
During planning, the cutter will determine the best possible shapes of the diamond in order to minimize losses and maximize the yield of the rough stone. Generally, the rough stone is mapped with "a SARIN machine" to generate accurate measurements.
With this data, a computer software is then used to formulate 3D models that will show the cutter the best ways to optimize the rough.
2. Cleavage/sawing of rough diamond
The cleavage process is the part that involves dividing the blank into separate pieces. This allows the cutter to work on the pieces separately and to use the blank in its entirety.
Mechanical sawing can also be undertaken at this stage. In the case of irregularly shaped blanks, the sawing process can also be carried out with non-contact cutting tools such as lasers.
3. Mechanical deburring of the rough diamond to round off the "angles"
After splitting the diamond, the rough stones are cut separately to make them round. This process is also known as girdling. What happens here is that two diamonds are placed on a rotating axis facing each other which is mounted in a dop at the end of a long handle and held against elle. They both then rotate in opposite directions and grind against each other to create a rough sheath. This process slowly rounds the diamond into a cone shape.
4. Polish the facets of the diamond
Once the rounded shape of the rough is formed, the next step is to create and shape the facets of the diamond. The cutter places the rough on a rotating arm and uses a wheel to polish the rough. This creates the smooth and reflective facets of the diamond.
It is interesting to note that this polishing procedure is divided into two steps: blocking and brillianteering.
In the modeling process, 8 pavilions, 8 crowns, 1 culet and 1 table facet are added to make a single cut stone. The importance of this step is to create a model for the next step.
The diamond cutter will then finish the work by adding the remaining facets, which will bring the total number of facets to 57. He has a great responsibility, as it is at this stage that the fire and brilliance of the diamond are determined.
5. Inspection of the polished diamond (quality control)
The last step is the inspection process. It is at this stage that the diamond is checked to ensure it meets the specifications set by the manufacturer. If necessary, the stone is sent back to the polishers for some touch-ups if elle does not meet quality control standards.
6. The diamond certificate for quality assurance
Once a diamond has been cut, it is usually sent to gemological diamond laboratories to obtain a grading report. This will not only increase the value of the diamond, but also help people buy the stone with confidence.
Check out our page on diamond certificates to learn more
Do you want to become a diamond cutter?
If you are interested in the profession or if you wish to enroll in a diamond cutting school, check out the following websites for more details.
American Institute of Diamond Cutting – In addition to offering courses, they also sell useful manuals for references on rough and colored diamonds.
Corlia Roberts Diamond Education College - Based in South Africa, they are one of the most recognized schools on the continent. At the end of your studies, the knowledge you have acquired will open the doors to careers in the industry.
Harry Oppenheimer Diamond Training School - This institute is a joint project between De Beers and the Diamond Foundation of South Africa, in Johannesburg. The courses offered prepare you for the real cutting of diamonds and the skills needed to solve the industry's problems.
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