Natural, Simulated or Dyed
Some opals have been
created in a laboratory. These synthetic or cultured opals are often difficult
to identify without laboratory tests. But there are some clues. First, if the
stone has an extraordinarily bright play of color, it may be a synthetic. Next
look at the pattern. Most synthetics have an overly regular pattern that looks
too consistent to be natural. They also have a roundish globular (snakeskin)
pattern. From the side, high domed stones will frequently look like the play
of color is in columns going from the top to the bottom of the stone. Often
they feel a little light, too. None of these characteristics prove that the
stone is a synthetic, but taken in combination they should make you very suspicious.
The Gilson Company,
which produces most synthetic (or created) opals , has changed its process to
produce more natural patterns. The snakeskin pattern is gone. This has made
it increasingly difficult to determine when a stone is a synthetic by visual
Simulated or Imitations
The distinction between
an imitation and a synthetic is one of chemistry. If a man-made stone has the
chemical makeup of its natural counterpart, it is called synthetic. If not,
it is called an imitation or simulated.
is a stone made in Hong Kong and sold under the trade name Opalite. It is as
light as a feather, it was obviously very soft and would not stand up in fine
jewelry, but is used in costume jewelry.