Glossary: Cabochon: What It Is And Advantages Of A Cabochun Cut
What is a Cabochon?
A cabochon is a particular kind of gemstone that has been polished and shaped, rather than faceted. In turn, these gems usually have a flat back and domed surface.
One of the simplest and oldest cuts, cabochon cuts are quite popular for opaque gemstones, softer gemstones and gemstones with unique displays such as an asterism: a stone with a star shape on its surface. Onyx, opal, turquoise and lapis are other examples of stones and ornamental jewelry materials that are often fashioned into cabochons. Sometimes, lower-quality precious and semi-precious gemstones, such as citrine, amethyst, garnet and ruby, are also cut into cabochon.
How Are Cabochons Cut?
Cabochon cuts begin with the selection of a suitable rough stone. Just about any gemstone can be used; but some gemstones, like the moonstone or opal, are preferred for their reflectivity and opaque appearance.
Once the stone is selected it is “slabbed,” a term that refers to cutting the gemstone into 1/4- or 1/2-inch thin slices. After placing the slab on a flat surface, a specific template and scribe are then used to mark the final shape of the cabochon.
After the shape is etched onto the raw slab, the Lapidary (a person who cuts and polished stones) uses a trim saw to cut around the stone. To grind the gemstone more accurately, cabochon machines use silicon carbide or diamond wheels. Water is often added to cope with intense heat from friction.
Finally, the gemstone is “dopped.” This involves the application of jeweler's wax to affix the stone to a “dop stick” which is basically a wooden dowel. The remaining excess stone is then ground away until it fits within the template line. Once the shape is set, the stone is sanded and then polished using a special kind of resin wheel and a polishing pad.
Advantages of a Cabochon Cut
While nearly any gemstone can be made “en cabochon,” opaque stones tend to be the most popular. Ultimately, the goal of the cabochon cut is to make the stone appear denser and fuller, as opposed to more brilliant, which is why most gemstones are faceted.
Certain gemstones have unique properties that are only visible when carefully cut en cabochon. These include:
Asterism: An attractive star-like effect produced by sapphires and rubies
Adularescence: A bluish, milky luster produced by a small number of gems such as moonstones
Chatoyance: Commonly referred to as the cat’s eye effect, this is produced by cabochon quartz and some other gemstones
Iridescence: Seen with gemstones such as opal, this phenomenon refers to the shifting colors depending on perspective
Cabochon cuts are also commonly preferred when a stone is translucent or has too many imperfections for faceting. Cabochons will retain a gem’s color but help obscure any scratches that might otherwise appear on the surface. This also makes cabochons ideal for softer gemstones that are typically below a 7 on the Mohs scale for hardness.
Gemstones are usually chosen to be cut into cabochons or facets based on their quality and/or optical properties. Most people tend to gravitate towards faceted gems because they reflect light better and have an alluring sparkle that’s typically associated with jewelry-grade gemstones. They also tend to better suit elegant and sophisticated styles of jewelry.
Cabochon gemstones are generally best suited for boho or more casual styles of jewelry. That said, they can certainly be crafted into highly stylish pieces in the hands of an especially skilled jeweler. A good example is John Atencio’s gorgeous Bermuda collection. Inspired by the startlingly beautiful blue-green waters of Bermuda, John blends gentle curves with matrix turquoise cabochons and scintillating pave diamonds for a brilliant 14 karat gold collection. If you have an affinity for cabochon, consider adding a piece from Bermuda to your jewelry collection.