Happy to help…some other points occur to me. If you are having rough
cut or recutting stones, your yield is a prime consideration. The old rule
of thumb was that you bought in grams and expected a 20% yield, so you
bought in grams and expected the same in carats. Get a 1 gram (5 ct)
piece of rough and expect to get a 1 ct stone out of it. However, it all
depends on the shape of the rough and the cut chosen by the cutter.
If the shape says “cut me as a pear” and you cut an oval, you are going
to lose weight. The cutter can also use a deeper cut for stones that have
the depth and a shallower one for those which are thinner. Bottom line,
the cutter I use has an average yield of about 35%, which is 175% of
the standard 20% figure. If you are cutting emerald cuts from tourmaline
crystals, your yield may approach 50-60% because of how similar the
shapes are. If you work from preforms which are already ground to shape,
you can get 70 to 90% yield. Recuts can be similar in terms of yield if you
can use a similar shape and don’t have to cut out a lot of inclusions.
So if your material is expensive, it pays to find someone who is good at this,
which, unless you are very, very lucky, will mean finding a custom cutter and
dealing with him or her by mail. Anybody can chuck a piece of amethyst in
their machine and cut a round out of something that should be cut as a rectangle,
because the round is more brilliant and easier to cut and because your time as
a cutter is worth more than the material you are grinding away. However, when
you are cutting good tourmaline at $200/ct, you want that last half carat ($100!)
and if you are cutting sapphire at $500, you want that last tenth of a carat ($50).
I’m a good cutter and would like to think I could do a good job on tourmaline,
but if I have a really fine sapphire that might finish over a carat (a magic break
point for value) but might not, I would probably farm it out to my go-to cutter.
Tell you a story…I ran into some small spinels last night in my stock. I don’t
think I paid much for these and they are not well cut, but there are a couple of
reds in there which are possibly worth $1000/ct. They need to be recut on the
pavilion so that they are not windowed…they are 1.2 ct to 0.8 ct. I don’t want
to lose more than 0.1 ct if I can help it, so my go-to guy will be instructed to
just move the pavilion facets to just above the critical angle. If he does well,
I’ll have something that looks real good and retails at $1000/ct instead of $750/ct.
$500 instead of $375. So you can see why he is worth $50 to $100 per stone…
Help, I’m talking about gem cutting and can’t shut up…LOL…hope this is helpful.
Do not be afraid to deal with custom cutters who come well recommended. They
will not disappoint you…if they did, their reputation would tank in a NY minute.
The colored stone world is a small one and word gets around fast.