Gemologically, the term "cat's-eye" used by itself is correctly
applied to only one gem: the greenish, grayish to amber type of
Even when the alexandrite variety of chrysoberyl is chatoyant (in
addition to exhibiting color change!) it's called "cats-eye
alexandrite," not just "cat's-eye."
Of course it's one of those terms that over time has come to be used
for any gem that exhibits the "eye" effect, most commonly quartzes
like tiger's-eye and hawks-eye. I own a cat's-eye opal triplet from
the Spencer,Idaho opal mines. Natural cat's-eye precious opal has
now been recognized from Australia and there's opalite from Africa
and Brazil that exhibits fine eyes when properly oriented. Eyes can
occasionally be fashioned from many gem species: feldspar,
tourmaline, scapolite, beryl, etc.
One of the very best "eye" stones is sillimanite because it can be
very close in appearance to chrysoberyl though it has very different
physical properties. I can supply a range of very reasonably priced
cat's-eye sillimanites from inventory. These stones "blink" when
rotated in the proper light and display the famous "milk and honey"
effect. I can usually supply chrysoberyl and alexandrite cat's-eyes
by special order if I know a customer's specific needs and price
Please email me off-forum if you have questions.