What is truly a cabochon?

If you think it is a cab, post it in the cab forum. Somewhere there might be a line between a tumbled stone and a cab. My cabs are done without tumbling but they are not calibrated and won't fit in standard settings. rgcopleland does the shaping with wheels and vibe tumbles for polishing. The most general definition of a cab is a stone used to make jewelery and with wire wrapping that is pretty open. A lot of my work falls outside that definition and I think of them as that work as mini sculptures.

I voted "couldn't care less" too. Look at all the commercially available "cabs" that have to be assembly line, machine cut. I think if it looks like a cab, feels like a cab, works in jewelry or other display methods like a cab, then ....................................
IT'S A CAB!!!!!!!!!!! ;D ;D ;D ;D ;D

what i mean is 400 rpm fast enough?

A cabochon or cabachon is a gemstone which has been shaped and polished as opposed to facetted. The resulting form is usually a convex top with a flat bottom. Cutting "en cabochon" is usually applied to opaque gems, while facetting is usually applied to transparent stones. Hardness is also taken into account as softer gemstones with a hardness lower than 7 on the Mohs hardness scale are easily scratched, mainly by silicon dioxide in dust and grit. This would quickly make translucent gems unattractive. Instead they are polished as cabochons, making the scratches less evident.

The one notable exception to this is the case of asteriated stones such as star sapphires and chatoyant stones such as cat's eye chrysoberyl, where a domed cabochon cut is used to show the star or eye, which would not be seen in a facetted cut.

The usual shape for cutting cabochons is an oval. This is because the eye is less sensitive to small asymmetricalities in an oval (as opposed to a round shape), and because the oval shape, combined with the dome, is attractive.

The normal procedure is to cut a slab of the rough rock, then to stencil a shape from a template. The slab is then trimmed to near the marked line using a diamond blade saw - called a trim saw, and sometimes followed by nibbling to the line. The purpose of nibbling is to speed the shaping of the material when using silicon carbide grinding wheels. Most modern lapidary workshops and production facilities have moved away from silicon carbide to diamond grinding wheels or flat lap disks.

Once the piece is trimmed and nibbled, it is usually mounted on a handle to assist manipulation. This procedure is called dopping: It is normally done by adhering the stone with 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.



That is the Wikipedia entry.

Calibrated cabs with a bezel have features a jewler can exploit, and they command more money. Except I think the fat oval with the flat back is like my grandmother's cab.

But, non-claibrated flat on the back, domed on the front, created with a dop stick, is no different in value from a ground on both sides and tumble finished piece - except I think the latter is nicer and more useful.

They do command less value because they begin to look like pendant beads (w/o a hole) and those are sold pretty cheap.

So, I look for the nice scene/pattern for the pendant stones I make. Others get tumbled as shapes and I might give nice ones to a wire-wrapper, or other ones to kids. In freeform tumble finished it is all about material and pattern.

Just my opinions