A cabochon (/ˈkæbəˌʃɒn/), from the Middle French word caboche (meaning “head”), is a gemstone which has been shaped and polished as opposed to faceted. The resulting form is usually a convex (rounded) obverse with a flat reverse. Cutting en cabochon (French: “in the manner of a cabochon”) is usually applied to opaque gems, while faceting is usually applied to transparent stones. Hardness is also taken into account as softer gemstones are easily scratched, mainly by silicon dioxide in dust and grit. This would quickly make translucent gems unattractive—instead they are polished as cabochons, making the scratches less evident.
The usual shape for cutting cabochons is an ellipse. This is because the eye is less sensitive to small asymmetries in an ellipse, as opposed to a uniformly round shape, such as a circle, and because the elliptical shape, combined with the dome, is attractive. The procedure is to cut a slab of the rough rock with a slab saw, and next to stencil a shape from a template. The slab is then trimmed near the marked line using a diamond blade saw—called a trim saw. Diamond impregnated wheels or silicon carbide wheels can be used to grind the rough rock down. Most lapidary workshops and production facilities have moved away from silicon carbide to diamond grinding wheels or flat lap disks.
Once the piece is trimmed it can be “dopped” or completed by hand. “Dopping” is normally done by adhering the stone with hard wax onto a length of wooden dowel called a “dop stick”. The piece is then ground to the template line, the back edges may be bevelled, and finally the top is sanded and polished to a uniform dome. Sometimes the pattern is too large to look good in a small stone. Or the pattern looks better in a round or a free form shape. Sometimes the pattern is too large to look good in a small stone. Or the pattern looks better in a round or a free form shape.
Some shapes are very unique. These inspire the jeweler or wire wrapper to be very creative and make for a very unique piece of jewelry. Some shapes are common: ovals, rounds, triangles. Shapes that aren’t a standard shape are called freeform. Some freeforms are so unique you may never see another stone cut that way again. But most freeform shapes will be repeated. Even though the shape is the same, the size, color, or pattern of the gemstone material will vary-insuring you still can create a one of a kind piece.
Each custom cabochon cutter may have their own shapes or names for those shapes, but often the shapes will be similar to another cutters. So what do you do when you see a shape you really like and want to find more of the same? [COMPARE INVENTORY TO THESE SHAPES & INCL. AS APPR.: https://www.barlowsgems.net/guide-to-designer-cabochon-shapes/ & http://blog.beadsofcambay.com/gems-101-understanding-different-gemstone-cuts-shapes/]