Subject: LapDigest Issue No. 120 – Mon 3/2/98

Subject: RE: How Do I Cut A Cat’s-eye Chrysoberyl

The simplest and easiest way to orient any chatoyant
phenomena is with a commercial product known as Star
Refractol and a good light source. The Sun is the least
convenient and most superior, I use a ‘Maglite’ a powerful
focusable flashlight. Chrysoberyl eyes are usually very easy
to find however and can be oriented sometimes with little
more than water or glycerine.

Hang or hold the light as directly above you as possible and
allow the eye produced in a small bead of liquid on the
surface of the gem to guide you to the position of the
required effect, this may take a few goes if the phenomena is
weak, as in most garnet and quartz. Asteriated and
adularescent stones are sometimes cut as eyes too and this is
the easiest way to find that eye. A detailed explanation and
drawings accompany the Star Refractol mentioned above.

A far smaller gem is obtained using the cruder and much much
faster method of grinding to a bead and polishing the eye
and cutting a flat opposite. This method is employed
extensively throughout the Far Eastern cutting houses and is
the reason for the enormous bellies seen on most star
sapphires and rubies.

I have cut Chrysoberyl cats-eye as small as 1.25mm dia. and
have never had a problem orienting them; polishing them
however…I have several tricks to achieving that if you are
interested, none of them involve vertical cutting equipment.

I hope this is useful,

Anthony L. Lloyd-Rees