Lapidary - An Introduction

A skilled lapidary is able to bring out the natural beauty of any rock. A professional lapidary can take any raw, rough mineral, rock or stone and cut and polish it until it's ready to be displayed, either on a shelf or as jewelry. Stones like onyx, agate and fluorite can be carved by lapidaries into functional things like plates, vases and bowls, or they can be carved into artful, representational sculptures also.

Cabochons (or 'cabs') are shapes that are flat on one side, are domed on the opposite side, and highly polished; lapidaries make these with a process that begins with a saw. Well, of course it begins with the rock itself, but rock hunting is another discussion entirely.
Once you get a rock in your hands, it needs to be sliced into slabs. If a lapidary is starting with a huge rock, they'll use a slab saw to bring it down to size. A typical slab saw incorporates a diamond-edged disc to cut the stone with, and is powered by a motor, and cooled and lubricated by a separate reservoir. This coolant and lubricant is usually oil or water. Of the two, water is much less of a mess, though oils are used by larger, commercial cutting houses. I've seen slab saws that run up to a gargantuan eight feet tall. That particular saw was a drag saw with a diamond blade, and it was mostly used to cut huge stumps or petrified wood.

These slabs are cut to many different thicknesses, dependent upon the size that the final cabochon needs to be and what material is being cut. If the final cabochon needs a high dome, the lapidary will cut a much thicker slab. Thicker slabs are also cut when the material being used is softer, as it will create much more waste when polishing and cutting.

A smaller version of the slab saw is called a 'trim saw'. These are also usually lubricated and cooled with water. These are generally used on smaller rocks, instead of the larger slab saw. The blade of a trim saw typically runs in two inch increments from four inches up to ten inches. Since this measurement is the diameter of the saw, an eight inch blade can only cut a stone that is less that four inches deep.

Once the slab has been cut by the lapidary, they then use the trim saw to hone the stone into something resembling the final shape. Lapidaries occasionally create calibrated shapes, and use a template to trace these onto the stone. Cabochons are usually calibrated into oval shapes, though circular and square shapes are also made.