Since the
late 19th century, Australia has been the
prime producer of gem opal in the world,
even today supplying more than 80% of the
world's production. It makes a significant
contribution to Australia's economy, including
the export market, so that its occurrence
has been extensively studied by the geologists
of the Departments of Mines of the three
opal producing States: South Australia,
New South Wales and Queensland. While there
are differences in detail in the geology
and manner of occurrence of the gemstone
in the various opal fields, the general
principles are closely related and are outlined
in the following sections. The locations
of the major opal mining areas are shown
here.
The first record of opal in Australia appears
to be the material found near Angaston in
South Australia by Johannes Menge in 1849,
a German geologist-mineralogist brought
out to that State to look for water and
building materials. A search of the Angaston
locality has, however, only revealed an
abundance of common opal, opal-CT. Opal
has also been recorded as being found by
gold panners in the Beechworth area of Victoria
in the 1860's. Dr W.D. Birch, of the Museum
of Victoria, states that this material was
described as 'fire opal', and there is no
evidence of precious opal showing diffraction
colours being found. Unfortunately, none
of this material appears to have been preserved.
The opal fields are in very isolated and
barren areas, so that a special way of life
has developed in these settlements. In earlier
days especially, they tended to be somewhat
lawless areas. |
