Jeweller - July 2022

AUSTRALIAN GEMSTONES
Colour Investigation
UNDERSTANDING GEMSTONE COLOUR
The distinctively elegant
gemstones of Australia
Aside from being a unique and naturally-rich country,
Australia not only boasts beautiful pristine beaches,
diverse wildlife, and the amazing outback. It is also
home to some of the most prized, rare and elegant
gemstones in the world.
Diamonds
Australia is home to some of the world’s oldest minerals and rocks, many of which are some of the
most sought-after gemstones by enthusiasts and collectors from every corner of the globe.
A beguiling, elegant and expensive byproduct of the most
common element found on earth – carbon – diamonds
are one of the most much-coveted jewels on Earth,
never ceasing to captivate and mystify people since the
dawn of time.
Diamonds are crystallised pure carbon and come in a
different range of colours such as brown, yellow, blue,
purple, red and pink, as a result of the inclusion of
minerals throughout their natural development stages,
spanning millions of years.
The distinctive properties - optical and physical - of
diamonds are reputedly the most lustrous among
transparent gemstones taken from the Greek word
Adamas or “invincible” given the stone’s hardness which
is rated 10 on the Mohs scale.
Australia has been one of the foremost sources of
diamonds worldwide, producing some of the finest and
rarest colour diamond pieces in the jewellery world.
Diamond production in Australia traces back to Bathurst,
New South Wales in 1851. Mining took off in 1867 which
produced large quantities of diamonds in the Copeton and
Bingara alluvial deposits until 1922.
From there small-scale, low-profile diamond production
and explorations continued throughout Australia.
During the mid-1970s, geologists discovered 23 low-grade
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FACTS
465
The Number of
carats of garnet
believed to be
owned by the
King of Saxony
1851
The year
Sapphires were
first extracted
from a NSW
river by miners
$10K
The cost per
carat high
quality black
opal
diamondiferous pipes in Ellendale in Western Australia.
That was followed by the discovery of alluvial deposits
at Kimberley’s Argyle in 1979 which would become the
world’s richest diamond deposit.
The Argyle mine was the largest diamond producer in
terms of volume, and supplied a third of the world’s
diamonds annually, and produced some of the rarest
stones with the highest diamond grades.
Beginning in the late 1980s, Rio Tinto – which operated
Argyle – supplied more than 90 per cent of the world’s
pink diamonds, until it mining operations ceased in
November 2020 after producing more than 865 million
carats throughout its 37 years of operation.
Diamond mining operations are expected to be
revived by the end of 2022 at the mothballed Ellendale
mine. The Merlin mine is targeted to resume operations
in 2023.
Here are some of the most notable diamonds from
Australia;
> A highly-sought 104.73-carat rough exquisite white
diamond was discovered in the Merlin mine in 2002
and is reputed to be one of the largest diamonds
found in Australia.
> Another rare piece is a 35.26-carat rough brown
diamond also unearthed from the Merlin mine in 2017,
which is considered to be the fifth-largest diamond
recorded from the continent.
> The Argyle Octavia is a 28.84-carat white diamond
discovered in 2019. It is one of the largest white
diamonds to come from the Argyle mine.
> The largest pink diamond in Australia is the 12.8-carat
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