Faceting refers to cutting and polishing the surface of a gem into many small, flat faces, or facets, in order to give the stone a brighter appearance. Light enters the gem and is refracted at different angles to be dispersed throughout the stone. Jewelers began developing faceting techniques during the Renaissance to increase the beauty of their gemstones. Facets, in some sense, embellish the crystalline structure that some gemstones form in nature.
The first rudimentary faceted gems are traced back to the late 13th and early 14th century Europe.
Previous to the innovation of cutting gemstones in this manner, they were made with a highly polished rounded top and a flat base. These stones were known as cabochons, and some of them also contained intricately carving. Cabochons are shaped and polished, as opposed to the cutting that is required in faceting. Some stones are still often created as cabochons, such as cat’s eye and moonstone.
The development of the technology to create facets was spurred on by innovation during the Renaissance. Developments in geometry and experiments with lighting led to a new understanding in the crafting of gemstones.
The most commonly known facet cut, the brilliant cut, was not perfected, however, until 1914 by Marcel Tolkowsky in Belgium. Faceting is now done by machine, with very precise measurement of the most beneficial angles for reflecting the light. The shaping and polishing of a gemstone is achieved using a lap, which is a metal plate that sands the gemstone into the desired shape.
One method of separating a gemstone is called cleaving. Cleaving uses the natural weaknesses found in the stone uses a sharp blow to separate the stone at that point of weakness. This method is often used for breaking a gemstone up into smaller pieces, it is not generally effective in creating facets.
The first category of faceted cuts are round cuts. These include the brilliant cut, the briolette cut, and the mixed cut. The round brilliant cut is the cut most traditionally associated with a diamond. The briolette cut creates more of a teardrop shape. The mixed cut is as combination of the brilliant cut and a step cut.
The other common category of faceted cuts are square cuts. These include the step cut, the cross cut, the French cut, and fancy cuts. The princess cut (in the main post image) also falls into the square cut category. The step cut is commonly seen in emeralds, and is usually used for darker gems, though it was originally designed for diamonds. The cross cut modifies the step cut to include more facets. The French cut is typically used on small stones and can create a rectangular, square, or triangular shape. Fancy cuts were originally designed for irregularly shaped crystals, but are now commonly used designs.
Branded cuts are another innovation of the jewelry industry. Branded cuts are trademarked by a company that allows them to be the only ones to produce gems of a certain cut. Example of these are “Hearts on Fire,” advertised as “The World’s Most Perfectly Cut Diamond.” or Coster Diamonds Royal 210 cut (below).
The parts of a brilliant cut gemstone all have their own terms. The girdle is the largest rounded edge where the top of the stone and the bottom of the stone meet. The crown is the top section of the stone, above the girdle. The pavilion is the lower section of the stone, below the girdle. The table is the flat surface on the top. It is the largest face or facet. The cutlet is the lowest part of the stone, usually a point or ridge at the bottom.
Header image by Stephen Durham