Stonesetting

Stonesetting is the art of securely setting or attaching gemstones into jewelry.

There are two general types of gemstone cutting: cabochon and facet. Cabochons are smooth, often domed, with flat backs. Agates and turquoise are usually cut this way, but precious stones such as rubies, emeralds and sapphires also may be. Many stones like star sapphires and moonstones must be cut this way in order to see the effects the stones have in them.

The other type of stone is generically called faceted, in which the stone has the general overall shape of the modern diamond, with a thin edge, called the girdle, the top angling up into what is called the crown, and the bottom angling down into what is called the pavilion. In the case of a cabochon stone, the side of the stone is usually cut at a shallow angle, so that when the bezel is pushed over the stone that angle permits it to hold the stone in place and keep it tight. In the case of faceted stones a shallow groove is cut into the side of the bezel into which the girdle of the stone is placed, and then metal is pushed over, holding the stone in place. Cabochons can also be set into prong settings of various kinds, but the idea is the same—it is the prongs going over the angle of the stone that creates the pressure that holds the stone in place.

Just as the angle of the sides of a cabochon creates the pressure to hold the stone in place, so there is an overlying principle in setting faceted stones. If one looks at a side view of a round diamond, for example, one will see that there is an outer edge, called the girdle, and the top angles up from there, and the bottom angles down from there. Faceted stones are set by "pinching" that angle with metal. If you imagine holding the girdle with the tips of your thumb and forefinger with both hands, that illustrates it fairly well. All of the styles of faceted stone setting use this concept in one way or another.

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