Posted on April 23, 2014 by Barbara Polinsky | 0 Comments
Diamonds have been sparkling in jewelry since the days of the Romans. As the hardest crystal on earth, fashioning them to reveal their brilliance has been a technological challenge. From the beginning, diamonds have been valued for their extreme hardness. They were considered divine and thought to impart invincibility. Perfectly formed crystals were very rare and prized above all other possessions.
The earliest known diamonds came from India where they were used as whole uncut crystals. Perfectly symmetrical crystals with lustrous facets were the ideal. It was taboo to cut them.
Over time, as new cutting techniques were developed in Europe, the taboo against cutting diamonds fell away. Stones were cut by eye and hand resulting in idiosyncratic gems with unique shapes and irregular facets. Preservation of carat weight was often the most important consideration. These “old mine” cut diamonds were characterized by fewer and larger facets that reflected light more softly. Light was drawn into the stone and less was reflected back to the eye. The resulting gems were beautiful, lively and unique.
As new sources of supply were developed in Brazil (1730-1870), South Africa (1870 to today) and many other countries around the world, diamonds moved from the nobility to the middle classes. Though diamonds remain expensive, they are plentiful and continue to represent wealth, status and permanence. New cutting technologies have resulted in a large variety of cuts yielding truly scintillating gemstones with brilliance and fire.
Originally, diamonds were only found in India. They were uncut as jewelers did not have the technology to cut the hardest substance on earth. Minerals adhering to the crystal were simply polished off to reveal the diamond’s natural octahedral or dodecahedral shape. This basic shape was also called the “point cut”.
The first cut developed was the “table cut” where one point of the crystal was cut off to create a table facet (5 crown facets). The opposite end of the crystal may also have been cut to create a culet. In the next advance, four facets were added to the crown and pavilion to create the “single cut” (9 crown facets).
The point cut, table cut and single cut produced stones that appeared quite dark or black – not what we think of when we think of a modern diamond!
Diamond cutting technology advanced in 1475 with the invention of a cutting and polishing wheel called a scaif. This wheel was powered by hand or foot. The continuous rotary motion enabled diamond cutters to facet whole diamond crystals more easily and accurately. This led to greater creativity and more variations in cuts.
A different cutting process developed in the mid 1500’s and resulted in the rose cut. A diamond was cleaved to create a naturally faceted flat-bottomed slice to which more faceted could be added.
As diamond crystal cutting expertise grew, more facets were added in the mid 17th century. The “double cut” or “Mazarin cut” had 17 crown facets and was the first “brilliant cut” diamond. The “triple cut” or “Peruzzi” brilliant followed with 33 crown facets. These diamonds were not truly round. Their shapes still reflected the original rough crystal with rounded corners and facets that were not symmetrical. These early brilliant cuts were tall, had heavier crowns, small tables and visible culets. Conservation of mass was still of major importance. These cuts are now referred to as “cushion” or “old mine” cuts.
In the late19th century, the “Old European” cut improved on the old mine cuts with true round shapes, shallower pavilions and reasonable symmetry.
Soon after the turn of the 20th century, diamond cutting technology was revolutionized. The development of electric polishing machines and motorized diamond saws combined to give the industry new precision and control. Diamonds could be cut with less loss of material. Until the motorized saw was perfected, polishing pulverized the unwanted mass and caused great loss of value. Now, chunks could be cut off and refashioned.
The modern “standard round brilliant” is the latest version of the brilliant. It is based on mathematical calculations for the ideal proportions to balance brilliance (the amount of light reflected back to the viewer) and fire or dispersion (the splitting of white light into spectral colors). This is the diamond we have come to know and love with its bright sparkle and intense play of color.
But, sometimes, we want a diamond with history. We can look back in time to find vintage stones with unique characteristics and a softer glow. Vintage stones are becoming rarer as many have been re-cut to more modern styles. But those that remain are often the best of their time as their beauty stands the test of time.
Some Barbara Michelle Jacobs custom pieces incorporating vintage diamonds.
Oval Solitaire with Branch Band
UPDATE: The Gemological Institute of America (GIA) recently created a new "Circular Brilliant" classification. Antique diamonds were cut with the intention of keeping as much of the rough stone as possible and to look brilliant under gas lighting which was in use at the time. Today, diamonds are cut to much different standards. As a result, GIA grading reports for antique stones often resulted in "poor" cut grades because lab was grading has been based on modern standards. Michelle Graff of National Jeweler recently wrote an informative article about this.