Cutting gemstones is an art form. Gemstones are cut to be used in jewelry or for decoration of various objects. The shape and cut of a stone can bring out its true beauty and luster. When two stones have the same clarity, color and carat, it is the gemstone cut that can make one stone shine over the other. The cut refers to the shape, proportion and finish that a skilled cutter can create. With the right tools and knowledge, a cutter can turn a gemstone into almost any shape desired.
There are fourteen common gemstone cuts: oval, round, emerald, pear, marquise, square, antique cushion, round brilliant, princess, baguette, octagon, trilliant, briolette, and round cabochon. Beyond these, there are also hundreds of cuts that have been used throughout history.
There are two styles of cuts used to create the vast array of shapes available: faceted and cabochon. Many stones are faceted, leading to a particular shape, while cabochons are simply cut into a dome shape and polished.
In faceting, small cuts are made on a stone to give it a particular shape. A professional cutter knows how many cuts to make and where to make them to form the desired cut and shape. The shape chosen for a stone is often dependent upon the structure of the stone in raw form, blemishes upon the stone and inclusions within the stone.
One well-known gemstone cut created with faceting is the round brilliant cut. This shape is often used for diamonds, the popular gem for engagement rings. A standard brilliant cut diamond has 57 facets or flat surfaces cut into the stone. Some stones such as square, baguette, octagon or emerald cuts have step facets that are parallel with the edge of the stone and "step" up to the flat surface in the middle.
The Millennium cut is perhaps one of the most difficult for a gem designer to master. With one thousand precise cuts across the stone, the Millennium was created in 1999 as a symbol of the coming millennium. The creation of this stone requires the perfect rough gem, a precise hand to place one thousand facets upon the small stone, and the right equipment to do the work. Because of the precise nature needed, the Millennium cut will likely remain a rare and highly valued shape.
For a simpler look, some prefer a gemstone cut that is shaped in a dome with a flat bottom. This type of cut is called a cabochon, and it can appear quite elegant in nature as it proudly exhibits the simple beauty of a great raw stone. Opaque stones, such as opals, are more commonly cut in this fashion.
A cabochon is formed from a rough gem by cutting it into a small slab and trimming it to the desired shape. Cabochons are normally cut in an ellipse, but they may also be round. Once the shape is evident, the back of the stone is flattened and the top is shaped and sanded into a dome. These last two steps are completed by hand.