Shop Tip:
There several reasons why one would decide to back a stone. But let’s consider what a backing is. A backing consists of a suitable material to add strength or to increase the thickness of a preformed cabochon. Many types of cabbing material are soft (less than 6 on a Moh’s scale), and are in need of a stronger foundation to prevent breakage either when setting the stone or during wearing of the finished piece.
There are many reasons for backing a stone: to accentuate a natural occurrence within the stone which might not otherwise be readily visible. An excellent example would be a white plume in a clear agate base. By placing the stone on a colored background the plume becomes more visible and enhances the stones salability. Sometimes a slab of material might not be the desired thickness needed to create the cabochon you envisioned or to off-set potential fractures which inevitably surface at the wrong time. This seems to happen when cabbing a stone from brecciated or cell type materials, (dinosaur bone). But more often than not, backing is chosen to off-set the high cost of a material. If you are paying $100.00 a gram or more for a material, you would want to cut it as thinly as possible to avoid waste of a valuable commodity. This is when backing is most advantageous.
What to use for a backing is a relatively simple decision. Determine what the end result is to be, will the backing be a color enhancement as mentioned in the above paragraph, or is it to over-ride the high cost of the working material. For starters I decide by choosing a suitable backing at least one level of hardness greater than the stone I am working on. Agates being one of the hardest are suitable for most jobs unless I am using it for color contrast. Since this is to be the bottom of the stone it doesn’t matter what color the backing is as long as it is stronger than the object stone. It should be cut at least 2mm. thick, thicker if additional height is needed for the bezel. If you are using it as a contrast then I would choose a solid color stone such as black agate, red jasper, or green imperial. Each color will lend a certain ambiance to the piece it is up to you to decide how it will affect the final outcome of the piece. I have even experimented with patterned stones for backing to add a different dimension to the work, sometimes it will surprise you.
Dragon
