Diamond cutting is the technological process used to shape a diamond. A cut does not refer to the shape (pear, oval) but to the symmetry, proportions, and polish of the diamond. The cut of a diamond affects the brilliance of the diamond, since a poorly cut diamond is less brilliant.
Cuts can be divided into
- Brilliant cut: Wedge-shaped, where the top is round, such as the Marquis, Pear and Princess.
- Step cut: Stepped, where the facets are applied in layers, such as the Usher, Trillion and Emerald.
Originally, the cut was only classical (round), but jewelers began to invent different shapes and another category appeared, the fantasy cut.
Various types of diamond cuts have been developed to enhance diamond properties. A diamond cut is defined by the symmetrical arrangement of facets, which together change the shape and appearance of the diamond crystal. Diamond cutters must consider several factors, such as the shape and size of the crystal, when choosing the best cut.
The practice of diamond cutting has its roots in the Middle Ages, but the theoretical foundations were not developed until the 20th century.
Design, creativity and innovation continue to evolve: new technologies, including laser cutting and automated design, make it possible to create cuts of incredible complexity, optical characteristics and minimal material consumption.
The most popular diamond cut is the modern round brilliant, whose facets and proportions have been refined through mathematical and practical analysis.
A round brilliant is subject to the most stringent standards and although the number of facets is fixed, the proportions can vary.
Also popular are fancy cuts, which have evolved from the round shape of the diamond and have different geometric shapes.
The advantage of the fancy cut is that the jeweler can play with the shape and create a new masterpiece every time.
The cut of a diamond is determined by experienced graders and higher grades are given to stones whose symmetry and proportions are closest to the standard cut.
Another important aspect is the quality of the cut within a particular shape, which greatly affects the price. Due to the fact that diamonds are one of the hardest materials, special diamond coated surfaces are used for grinding.
Different countries may have different cut grading standards, such as the American or Scandinavian standards.
Where are diamonds cut and polished?
The first organization of diamond cutters and polishers was established in Nuremberg, Germany in 1375, which led to the development of several types of diamond cutting. This refers to the shape of diamonds such as square, oval and others.
Diamond cutting and polishing is done in different countries like South Africa, Belgium, China, Israel, UAE, and USA, besides India. These places are major diamond trading centers, from where rough diamonds are shipped to India and the main processing centers in China.
This process requires a lot of skill to cut the rough diamond and give it brilliance. One of the important aspects of valuing a diamond is the perfect cut, which is considered along with other characteristics called the “four C’s” (carat, color, clarity and cut) in assessing the value of the stone.
Almost all diamonds are cut and polished in India, mainly in the city of Surat, but also in the Chinese cities of Guangzhou and Shenzhen. In recent years, India has held a share of between 19% and 31% of the global polished diamond market, while China accounted for 17% of the global share last year. New York is also a significant diamond center.
Are diamonds cut by hand or by machine?
After shipping the rough diamond to India, New York, Antwerp or any other city, a highly skilled diamond cutter starts the cutting process. He can choose to either do it by hand or use a machine. It is important to note that diamond cutting machines are very precise and useful tools, but hand cutting a diamond is an incredible craftsmanship.
How long does it take to cut a diamond?
To cut a 1-carat rough diamond usually takes 4–8 hours, but it can take much longer.
What are the stages of the diamond cutting process?
As stated above, diamond cutting is the process of transforming a rough diamond into a cut gemstone. It requires special knowledge, tools, equipment and methods because of its high complexity.
The following steps include a simplified process for cutting round diamonds:
- Planning. Advanced diamond planning is done using computer software.
- Marking. Designation of the best possible shape and cut of the diamond.
- Saw cutting of the rough stone. Since not all diamonds are cut according to the shape of the rough diamond.
- Blocking the 8 main facets of the pavilion. These facets are divided into 4 corners and 4 pavilions because the atomic structure of the diamond causes the corners and pavilions to move in different directions.
- Crown. The crown consists of eight main facets divided into four corners and four bezels.
- Finishing. Providing a perfectly round and smooth diamond edge. All 16 main facets are polished. Eight stars, 16 pavilions and 16 crown halves added and polished.
- Quality Control. Symmetry control, polishing and faceting (corners) after the diamond is finished.
How are diamonds cut?
Over time, the diamond cutting process has undergone changes due to the advent of new and improved technologies.
One significant transformation in diamond cutting was the introduction of a machine known as a skiff in the 1400s. This machine was used to cut the facets of diamonds and showed their true beauty for the first time. It opened up new possibilities to achieve complex shapes, cuts and designs that were previously unknown.
A diamond is cut using a steel blade or laser, such as the Sarine Quazer 3, by cleaning or sawing. The rough diamond is usually set in a wax or cement mold to hold it in place and then split along its weakest surface, called the tetrahedral plane. If the weakest point is missing, then a sawing process is used.
After the stone is analyzed and split, it is treated or girdled in one of three ways. This is most often accomplished by rotating axes on which the cut diamonds are mounted opposite each other, rotating in opposite directions. This allows the opposite sides of the diamonds to rub against each other to produce a smooth and round shape.
It is also possible to treat diamonds with a laser or to grind them against a copper disk coated with diamond dust, which acts like sandpaper. The final step is polishing, followed by a final inspection, sometimes including cleaning the diamond with acid to achieve a clear shine.
Once the cutting and polishing processes are complete, the diamond is ready to be appraised and sold.
How is a diamond polished?
After forming the rounded shape of a rough diamond, the next step is to create and shape its facets. The cutter places the material on a rotating arm and uses a rotating wheel to polish the rough material. This creates smooth and reflective facets of the diamond.
Popular diamond shapes
Here is the list of the main types of diamond shapes:
