A cabochon is a gemstone which has been shaped and polished, usually with a convex top and a flat bottom. Opaque gems, such as cats eye or jasper, are usually cut with a smooth rounded top. Transparent stones, on the other hand, can be cut smooth or faceted. The faceting helps the transparent cab reflect more light.
The process for making a cabochon starts with choosing a slab of the rough rock. A shape is drawn on the slab and the slab is then trimmed to near the marked line using a diamond blade saw, also called a trim saw.
Once your piece of stone is prepared, you use hot wax to attach a small, wooden dowel to the flat side of the cab. The dowel is called a dop and is used to hold the stone while you cut and then polish it on the cab machine.
First, the stone on the dop is rounded off on the edges. Then as the process progresses, the cab is shaped and then polished. Once the cab is finished, it can be set in a freezer for a few moments. This allows the cab to be easily removed from the dop.
The time it takes to cut and polish a cab depends on the harness of the stone. The harder the stone, the longer the process will take.
***My bead store, Tiger Beads, has a large selection of semi precious designer cabochons in many different stones, different sizes, and faceted and smooth domes. Take a look at the variety of different ways a stone can be shaped.