how do cutters pick cuts?

[sonyachancs]

sorry if this is a repeat of other threads (but I searched and couldn't seem to find something similar)..

I recently just asked jeff davies to cut me an ammy, and was asking him if he could this cut or that cut for me on the rough - when I asked about using a portugese, he said "not sure how good it would look in this color". it seems, eventually, that he might be trying out a portugese on the rough anyway,

but that's not the point. the question is, what determines the cut on a stone? I'm guessing it goes beyond the obvious i.e. the rough is this shape, and so the cut is this shape?

 

[kenny]

If a business person is cutting I hope they'd be cutting to maximize profit from each piece of rough.

Hobbyist cutters don't have the same pressure.

 

[corundum_conundrum]

RI of the stone, Color, shape of the rough, amount of material and cetera...

With respect to your amethyst, it might be the case that the rough is somewhat dark. Since portuguese cuts can darken the stone (or so I've heard many cutters say) it might not be advisable.

 

[chrono]

It is a balancing act as the others mentioned; shape of rough, size of rough, colour of rough, refractive index, size and location of inclusions, pleochroism, zoning, etc.

 

[JewelFreak]

Also how the color runs. Most gems are cut with the table perpendicular to the C axis, but sometimes not.

 

[ruffysdad]

Actually, picking the cut is fairly easy. The stone tells you . First of all is the general shape of the rough. Will it yield best if cut to an oval. round, barion or rectangle. That's pretty easy so far but now comes the part where experience pays off, the cut itself. A cutter has to look hard into the stone and see where any inclusions are located, and decide whether to hide them or cut them out entirely. Look at the intensity of the color, and judge by experience what kind of cut will bring it out. I've resurrected some badly cut garnets by simply shallowing out the pavilion which was cut at too high of an angle and/or laying a checkerboard on the crown.

Pete

 

[lelser]

We design most of our cuts, and for a particularly fine piece of rough will often design just for it.

It's all about the overall value of the piece. It needs to be good yield but I've sacrificed yield for colour many times.

Cheers,

Lisa
www.lisaelser.com

 

[sonyachancs]

thank you all, and especially the cutters for chiming in! I figured it had a lot to do with art/ experience, but it's pretty cool to know that there's a sort of science to it. I suppose there would be also a fair spread of chosen cuts for 'equivalent' roughs to cater to a wide range of customers.

2. It allows a client to be able to "see" what they will be getting via the use of rendering software. One can even model and render concave cut gems rather easily once the design is completed. The attached image is of a concave cut aqua that I modeled just for kicks, (the stone has never actually been cut).

how accurate are these CADs actually? I'm just wondering because when used to design jewelry, colors of metal and details can be accurately rendered, but with stones, where angles and colors change with the cut of the stone, what sort of accuracy are you seeing from your stones?

also, that is a beautiful cut, no matter how untested. not one for concaves but they sure are impressive!