An understanding of the cut of a gemstone begins with the shape of the rough stone. Respecting the original shape in the cutting design will allow eliminating the smallest fraction of the gemstone as a whole, thus preserving the carat weight. This rational will apply systematically on highly expensive roughs such a diamonds. In a way, it is the rough diamond and its quality (clarity and color) which will dictate on which cut to choose. Other gemstones, on another hand, will gain value thanks to their cut which will enhance either their color, or give them a rare artistic appeal in the case of stone carvings for example. In this case, the original carat weight matters less. As for any abundant commodity, gemstones usually found in large roughs will have less value per carat. But exceptional cutting or carving will add an artistic value, and this implies a premium which will be stimulated by demand.
Another important factor taken into consideration at the very start of the cutting and polishing process are the hardness (based on the Scale of Mohs) and nature of the inclusions. The Mohs scale of mineral hardness is a qualitative ordinal scale that characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material. Carvings and fancy cuts will be suited to lesser ranked gemstones on the Mohs scale, whereas the hardest such as diamonds, sapphires and rubies will be usually cut in the traditional shapes. Inclusions are one of the most important factors when it comes to gem evaluation. In many gemstones, such as diamonds, inclusions affect the clarity of the stone, diminishing the stone's value. In some stones, however, such as star sapphires, the inclusion actually increases the value of the stone. For obvious physical causes, a highly included stone will be challenging to carve and cut compared to a clear stone.
The cut of a stone is directly influenced by hand, as the rest of the stone’s characteristics are determined by nature. It refers to shape (the face on appearance of the gem) and cutting style (the arrangement of the gem’s facets). This aspect of a stone is probably one of its most artistic possible qualities, as it directly refers to the savoir faire of a cutter to enhance the natural properties of a stone. When appreciating a jewel with a center stone, it is therefore essential to study the quality of its cut. A trained eye can easily notice a correct balance of proportions and geometry, or the delicate poetry resulting in a detailed carving.
Diamond is a natural crystalline lattice with cleavage planes that gem cutters use to "rough" a stone before facets are cut. These cleavage planes welcome cracks that can run unopposed for significant distance, and it just takes a sharp strike at the right angle to trigger the cleavage.
Shawish Jewellery, a company based in Geneva, unveiled at Baselworld in 2012 what they billed as ‘the world’s first diamond ring’, which took one year to construct. Cut from a single chunk of rough diamond, the ring original designs were copyrighted and released in April 2011.
Unique laser equipment was purchased to ensure the quality of the diamond didn’t suffer through its construction. A hole was cut right through the middle of the huge rock, the action potentially altering the diamond’s original molecular structure. Of particular concern were the stresses involved in putting the ring on and taking it off, and the force exerted upon the ring when the wearer bends their finger. Weight gain or finger swelling could be disastrous. The 150-carat ring has been valued at around USD $70 million.
Emeralds get their name from the old French word "esmeraude" and the Greek "smaragdos" which simply means "green gemstone." The oldest finds are from the Red Sea in Egypt but these mines, active between 3000 to 1500 BC were depleted by the time they were rediscovered in the early 19th century and now only produce lesser quality emeralds. These mines later became known as the Cleopatra mines and were thought to be the only source of emeralds in the world until 1558 when the Spanish discovered emerald mines in Columbia.
Emeralds are actually fairly hard but nearly all emeralds contain surface fissures, inclusions, and other flaws referred to as "jardin", meaning garden, which describes the silky web-like or mossy appearance of the tiny inclusions found within the emerald. Inclusions and flaws are expected in emeralds and flaws are so evident, in fact, that emeralds are generally graded by the naked eye instead of with a jeweler's loupe as say for a diamond. They are considered flawless if there are no flaws visible to the naked eye.
One of the most famous carved emeralds, the The Mogul Mughal Emerald, is an emerald cut tablet weighing 217.80 carats, and dates back to the year 1695. This large gemstone is engraved with Islamic prayers at one side while the other one is adorned with beautiful flower engravings. Today it is at the display at the Museum of Islamic Art, Doha, Qatar, after it was acquired from the Christie's at the US $2.2 Million.
As an example of contemporary interpretations of emerald carving and cutting mastery, London based designer Glenn Spiro celebrated the art of cutting emeralds with this one-of-kind carved emerald ring made of a complete piece of emerald stone, with a gold inlay.
A typical work of G London, this ring is a tribute to the beauty of nature and precious gemstones when the hand of Man highlights the properties of Mother Nature’s treasures.
For more artistic variations of stone cutting, some contemporary master cutters explored far their art to celebrate the beauty of stones, and I can only think of two of the most well-known designers in the world today to represent this magnificent trend: Mr. Wallace Chan and Mr. Sevan Bicakci.
It took Chinese designer Mr. Wallace Chan 13 years to invent a technique of his own: the “Wallace cut”, a way of carving a human face into a precious stone. From the back of the stone, all you can see is the curve of a nose, cheeks and hair, but from the front a detailed three dimensional face appears in portrait and in profile.
This work resembles greatly another master of the craft located in Istanbul, Mr. Sevan Bicakci. As it was explained to me during my visit in his showroom, a modified dentist's drill is used to make small detailed changes on the stone. Most of the designs are made under water to dissipate the heat generated by the high powered drill, to prevent damage to the material. Over the years, he perfected his art by applying small layers of lacquer to create poetic optical painting effects, often celebrating the cultural heritage of Istanbul.
These artists here did not use traditional precious stones, choosing gems with lower hardness to explore further the craft of stone carving. Wallace Chan here used a beryl (Aquamarine), while Sevan Bicakci often picks Quartz. The craftsmanship and the artistic interpretations in their designs give to each stone and jewel uniqueness and character.
Parisian designer Madame Victoire de Castellane did explore for the house of Christian Dior the beauty of stone carvings. One of the most poetic illustrations would be the recent variation of her signature “Pre Catelan” rose themed rings with hand carved amethysts (Quartz), which came at there launch in 2013 also with a high jewelry limited edition made hand carved rubellites (Tourmaline) set with diamonds.
With jewelry, one must always consider the intended use. It would be reasonable for the ring to be displayed inside a case. But would it stand up to being worn, and would it be robust enough to be worn a few very special times? It is up to the collector to decide, after being initiated to the beauty and complexity in the art of cutting a rock from Mother Nature.
- "The first diamond ring", Diamond, Shawish Jewellery
- The "Mogul Mughal" Emerald
- Emerald ring, Glenn Spiro
- An example of the "Wallace Cut" on aquamarine, Wallace Chan
- Quartz and diamond ring, Sevan Bicakci
- "Pre Catelan" amethyst and diamond ring, Victoire de Castellane for Dior Joaillerie