How to set pyramid cuts?

[Cave Keeper]

Does anyone have any ideas on how dark sapphires cut in shapes similar to a pyramid can be set?

There''s one 2 carat stone described as triangular cabochon, and there''s another one just over half a carat that is a 3-sided pyramid with very rounded corners and apex described as pear shape.

This kind of shape strikes me as a kind of cut that seems to ignore the main reason (the theory of which I confess I''m not well versed in, in the first place) why the brilliant cut was invented.

 

[Michael_E]

Cave Keeper,
A clear gem with a three sided pavilion will form what is called a "retro reflector" if the facets are cut at just the right angles. One of the neat things about this is that, over a certain band of entrance angles any light ray entering this will be reflected back at the same angle and direction that it entered from, (although not along the same path). You can make all sorts of cool gems using this idea, but they are kind of hard to set. I''ve got a pale citrine that I cut to another persons design, (can''t remember who designed it), using a sort of geodesic dome crown and a retroreflector pavilion that has only three facets. Very bright and interesting stone. I''ll post a pic if I can find the darn thing.

Anyway, setting something like you''ve described, with rounded edges, would require some novel setting like wire wrapping or a wide banded bezel, something that could get a grip on it.

 

[Cave Keeper]

Date: 8/30/2005 2:30:21 PM
Author: Michael_E
:
A clear gem with a three sided pavilion will form what is called a ''retro reflector'' if the facets are cut at just the right angles. One of the neat things about this is that, over a certain band of entrance angles any light ray entering this will be reflected back at the same angle and direction that it entered from, (although not along the same path).:

Now that''s the anti-Evil Eye solution!