There are a couple of safe ways to do it so your choice should
be based on the draft angle of the prongs and the quality of the
stone. Any way you do it, the trick is to apply the pressure to
the girdle away from the points and not on the crown and pavilion
as you would with most other stones.
Check the corners of the stone for fractures or any other
weakness you can find and look at the eveness of the girdle. If
you find a weak corner (fractures, etc. from cutting and
polishing the stone), make sure you know where that is when you
set the stone since that is the corner you don’t want to apply
any pressure on. Also, knowing where the girdle is thickest will
tell you which corner can apply the most pressure to all the
others. Mrk the setting with a magic marker for all the weak
Then determine where you want the table to land when finished so
you know where the points must seat. With the stone in the
setting about where you want it seated, either scribe a line
across the two points of the vee or mark a small relief hole in
the crook of the vee with an 005 or smaller ball bur. (I normally
scribe a line since I have the stone in place and can’t get to
Take an 012 to an 016 hart bur and cut into the vee vertically
until the edge of the bur just reaches the center of the crook.
(this will create a little football standing on end.) The reason
for the vertical cut is to provide some relief for the both the
crown and pavilion keels allowing the facets themselves to hold
Try the stone now and see if there is any friction on any of the
points or resistance on any of the pavilion keels. If it is a
good stone, this is all the cutting you should have to do but if
you have a weak corner, you can now add an extra cut (but you
don’t have to do it to all the corners).
Take the same hart bur and now cut an horizontal mark out to
about two thirds the distance to the edge of the vee. (put the
cut in the center of your vertical football). This will move the
pressure outwards along the girdle and away from the weak corner.
Open the setting up so that two of the touching corners can
slide into their seats allowng the other two to drop down into
theirs. (Don’t ever try to “snap” the stone in.). Move the
diagonal prongs closer together until the stone is either tight
or at least locked into the seats. If the stone is tight, don’t
do anything else. If it is not, don’t keep trying to squeeze them
together. Instead, draw the individual vee’s together by
pinching them slightly where they touch the exposed part of the
Center and finish off the prongs as you normally would. There’s
a million ways to skin a cat, this is the way I normally do.
John Gavin Findings, Inc.
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