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A cabochon (; ) is a gemstone that has been shaped and polished, as opposed to . The resulting form is usually a convex (rounded) obverse with a flat reverse.9780756609627, DK. ISBN 9780756609627 Cabochon was the default method of preparing gemstones before gemstone cutting developed.
9781473395398, Read Books Ltd. . ISBN 9781473395398
In asteriated stones such as star and chatoyancy stones such as cat's eye chrysoberyl, a elliptic dome cabochon cut can show the star or eye, which would not be visible in a faceted cut.
The usual shape for cutting cabochons is an ellipse because the eye is less sensitive to small asymmetries in an ellipse than in a uniformly round shape such as a circle. Additionally, the elliptical shape, combined with the dome, is considered attractive. An exception is cabochons on some watch crowns, which are circular.
The procedure involves cutting a slab of the rough rock with a slab saw, and then stencilling a shape from a template. The slab is then trimmed near the marked line using a diamond blade saw—called a trim saw. Diamond-impregnated wheels or silicon carbide wheels can be used to grind the rough rock down. Most lapidary workshops and production facilities have moved away from silicon carbide to diamond grinding wheels or flat lap disks.
Once the piece is trimmed it can be "dopped" or completed by hand. "Dopping" is normally done by adhering the stone with hard wax onto a length of wooden dowel called a "dop stick". The piece is then ground to the template line, the back edges may be bevelled, and finally the top is sanded and polished to a uniform dome.
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