We have an octagon tourmaline, about 8 cts., step cut. This stone
is dark blue with some green showing. The stone is the typical cut
along the crystal side with very steep pavilion angles on the ends.
This stone is also the kind with little or no light along the axis
of the crystal, meaning a look down the ends shows only darkness.
If the stone is recut to improve lightness and color, what is the
approach? Would bringing in the long side pavilion facets to a
shallower angle help? Would the correct approach be to bring in the
steep facets on the ends of the stone?
The stone is nice but simply too dark and not cut to proper angles
for tourmaline in the first place. With the dead axis along center
end to end, I am not sure what sort of recutting would improve the
lightness and color of the gem.
Any advice is greatly appreciated.
Tom
@Sp.T
It is quite possible that the steep angles onthe ends of the stone
are there for a reason. Usually because of the closed c-axis. if
they were cut at the “proper” angles, then they would not reflectthe
right color, and could look off color, or even just very dark
depending on the stone. Most dark stones can be lightened by using
shallower angles, or using similar angles, but with a pattern that
makes the overall stone shallower. The less material that the light
has to travel through, the brighter it will be in a dark stone like
this.
Mike
Tom,.
It sounds like a dark tourmaline that will most likely stay dark no
matter what you do. None the less, you might be able to lighten it
abit. I would say one thing might be to cut the side pav facets to
the proper angles first and see what that brings. Then bring them
in a bit at a time to see if you can improve color. Remember, you
are not cutting this stone for brilliance or scintilation…it is
long past that.
I would not bring the long end facets in. Tourmaline tends to just
blacken out if you do that. Leave the ends fairly open. After
these efforts, if the stone has not improved, you will just have to
accept it for what it is…a large dark stone. I have a
beautifully clear but dark forest green stone that no amount of work
would improve. I just keep it as a reminder that there are limits
to what a cutter can do!
Cheers from Don at The Charles Belle Studio in SOFL where simple
elegance IS fine jewelry! @coralnut2
Thanks for the responses. The info is good and on the money as I see
it. We will likely leaving the stone as it. I doubt much can be done
at this point considering the angles of the pavilion facets on the
sides. The email with links was especially appreciated.
Thanks again!
Tom.