English: In the upper left we see a hunk of a rock. This rock is chalcedony or quartz. Such unfinished rock is called rough. In the upper right we see a finished piece called a cabochon. Cabochons, big or small, are often put into jewelry.

The rough is cut into a 1/4 inch thick piece called a slab which you see underneath the template. Some people use these to guide them to the eventual shape of a cabochon. Advanced cutters often work without templates.

Steel templates offer a variety of shapes from which to choose: ovals, circles, crosses, and more. Moving the template across the slab will eventually reveal an interesting pattern to mark off with an aluminum pencil.

Rock surrounding the pattern is removed with a trim saw, by cutting closely to the outside of the marked line. Cutting closely reduces the grinding required for the next step. A grinding wheel removes even more material, resulting in a flat ¼” thick stone with the desired overall shape.

Cabochons are concave, flat on one side, rounded on the other. A dome must be shaped at this point. A center line is drawn across the middle of the stone. With the grinding wheel of a cabbing machine, the side of a stone is worked away until a smooth, rounded rise to the center is achieved.

Polishing produces the final product seen in the upper right, a finished cabochon.

The chalcedony rock at the lower left has been tumbled in a rock tumbler. Another part of lapidary.