The art of cutting a diamond by hand: Part 1

Diamonds have been prized for their unique physical attributes for millennia, and their form has altered due to fascinating historical and technological discoveries. The allure of owning a diamond, cut by hand using the first pioneering techniques, is an investment in rarity and a craft which now very few possess. Because of their relative scarcity, these distinctive diamonds have become a favourite of discerning collectors and lovers of jewellery alike, due to their originality and old-world charm. 

Formed of crystallised carbon, diamonds are arguably the hardest substance on earth. Pliny the Elder, the ancient Roman philosopher stated:

‘These stones are tested upon the anvil, and will resist the blow to such an extent, as to make the iron rebound and the very anvil split asunder.’

Diamonds have been seen in jewellery since ancient times, with India being the world’s sole source of diamonds from the 4^th century BC, or earlier, until 1725. However, the technology did not exist for cutting a diamond, so prior to the 13th century they are seen in their most common natural form, an octahedral crystal. Though not technically a cut, since the diamond was largely unaltered, these are now termed ‘point cut' diamonds.

It wasn’t until the 13^th century that the first technique of cleaving a diamond emerged, allowing for additional planes to the surface of a diamond. The crystalline structure of a diamond is such that relatively weak planes exist in parallel layers throughout the stone from top point to bottom point. These can be ground down with the application of another diamond, and with slight force to this area from a thin blade, the diamond will cleave. The process of cleaving allowed for the removal of the top and bottom points of the octahedron, giving birth to the table cut diamond. This could also be achieved by sawing the diamond, an arduous task where the diamond cutter would use a thin wire and diamond powder mixed with oil.

One may ask, why add additional planes to the diamond's surface? One theory suggests that higher quality diamonds were kept in India for the local markets, with merchants also choosing the highest quality stones from the supply chain. Therefore, once on the European market, the diamond could have been fashioned to remove natural inclusions from these lower quality stones. 

The ability to grind further facets, would not be possible until the invention of the rotary diamond wheel during the sixteenth century, also known as a scaife. With a superior hardness, diamonds were cut in pairs by rubbing one against another. Diamond powder fell in the process, which in turn was mixed with oil and inlaid on the steel wheel. The diamonds were then held in cups of pewter and pressed against the wheel to create additional facets. 

In circa 1725 new deposits were discovered in Brazil, meaning India was no longer the sole source of diamonds. This discovery caused the price of diamond rough to drop by 70%! This allowed diamonds to be available to a wider audience than just European nobility. This propelled interest in the industry, including the advancement of diamond cutting techniques and technology, leading to cuts featuring more facets, such as the cushion old mine cut.

The discovery of the South African deposits in the 1860’s further increased interest due to the huge influx from the Kimberley mines, and in the early 1870’s, a major event altered the course of diamond cutting. Henry D. Morse and Charles M. Field established British and U.S. patents for steam-driven bruting machines in 1874 and 1876 respectively. The first electric bruting machine was invented in 1891. This allowed the girdle of two diamonds to be rubbed simultaneously in a circular motion which created a more symmetrical cut with a circular outline. In the latter half of the 20th century, diamonds were cut on mass by lasers, this modern cut is known as the round brilliant cut.

The vast collection at Berganza is comprised of vintage and antique diamond set pieces which have all been entirely crafted by hand. Their captivating irregular subtleties, coupled with their increasing rarity, makes their unique charm highly desirable and sought after. Most hand cut diamonds were subsequently unset and re-cut as technology advanced, rendering any such jewel a remarkable survival.