An introduction to Cabochons

Cabochons also called cabs are gemstones which are not faceted but simply polished on the surface. The faceting of stones became popular in the 15th century; cabs were used in the jewelry even before the 12th century. The gemstone which are opaque & have inclusions are suited for creation of cabochons. The softer stones get easily damaged from the silicon dioxide present in dirt and grit. Transforming them into a cab reduces the scratches on the surface. Sometimes the stone are cabbed to preserve the optical phenomena such as cat’s eyes, star effect, etc. Moonstones and amber are two prominent stones for jewelry making created using the cabbing process.

The cabs have a dome shaped top and a flat bottom. Upper area can be hemispherical if the dome is high. The ovalular cab stones take less time to set in the jewelry. Other than  cuboidal, teardrop, cubic and spherical shaped stone require complicated procedure. The gemstones with a hardness lower than 7 mohs such as sapphire, ruby and garnet are always cut into cab. Cabs are used in pendant, earrings and large men’s rings. They are set generally in bezel settings using glue.

If you are using a cab stone for jewelry making keep these points in mind -

• At time of purchase check the lower surface of the stone. A cab which is not flat will not be glued properly. Irregular bottoms don’t get fixed to the base metals. It’s likely to flip out of the jewelry.
• Look at the edges of the stones. A narrower bottom & wider topped stone cannot be used for jewelry making. On the other hand a stone with a wide bottom integrate easily. Straight edged stones are harder to set but with a extra glue can be placed well on the surface of the metal.
• Often jewelry makers prefer bulk gemstones cab purchase.
• The sides of the cabs should reflects the same angle on each side. If the stone reflex different angles it is poorly cut. You mightn’t achieve the desired look in your jewelry design using such a stone.
• The front surface of the stone should be plain and shiny with minimum visible inclusions. However, if you find a stone with an exquisite pattern forget it rules. Sometimes beautiful stone are formed because of the inclusions or irregularities on the surface.
• The is little 45 degree angular cut at the bottom from the starting to the ending point of the stone, only visible under a microscope. Without this cut your cab stone can shatter into pieces after being chipped accidently. One little crack on the surface and your cab is out, check for this cut while buying.

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