Opal Forms
Text by Len Cram(About
the author)
Australian opals are the finest in the world. They
have tremendous investment potential and are one of
the few gemstones which have appreciated at a steady
rate over the past 40 years. But before you race out
and buy one, learn a little about them in what form
they come and what is available.
They fall into three categories:
- solids,
- doublets
- triplets.
SOLIDS:
are natural stones which have been cut and polished
without being interfered with. Many have a natural potch
or rock back.
DOUBLETS:
are usually two pieces of opal cemented together.
They are made by cementing a layer of high?grade opal
to a black potch back, which enhances the colour. For
economical reasons, many have thin faces. But domed
cabochons made from good quality crystal opal, do in
many cases, resemble fine quality black opal, which
is due to the partial absorption of light by the black
back. Their value is only a fraction of that of a solid
black gem of the same quality. Although not always encouraged
by the trade as an investment stone, the better pieces
do bring a reasonable price and are certainly worthy
of a place in any good gem collection.
TRIPLETS:
are doublets usually made from a lower grade opal with
clear domed caps cemented to their faces. The hardness
of the cap may vary from glass to quartz, depending
on the quality of the opal. The cap not only protects
the opal but magnifies the intensity of the colour and
pattern, greatly enhancing the overall appearance.
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