Jeweller - August 2022

REVIEW
Gems
Pearls Part V: Examining the Exotics
Above: Moussaieff; David Morris; Clogau
Below: Kendra Scott; Amanya
To the average consumer, or even the
average jewellery sales assistant, pearls
are often known to be gloriously lustrous,
covered in glittering nacre, as close to
white as possible, and aiming to be
perfectly round.
But pearls may take many forms, borne
of a range of different sea creatures,
whether bivalve or gastropod, nacreous
or not.
Abalone - including Paua - pearls are
one of the better-known examples of
exotic pearls, given their popularity
and harvest in Australia’s neighbouring
nation, New Zealand.
A type of nacreous pearl, the most
well-known Abalone variety displays a
unique and highly recognisable multitude
of blues, green, and brownish colours
with high iridescence - the highest of the
pearl-bearing molluscs.
Abalones may be natural pearls, forming
without human intervention of any kind,
or cultured with the introduction of a
shell seed.
Natural Abalone pearls range greatly
in size, from small seed pearls to large
specimens of more than 70mm. These
are often baroque in shape, and more
rarely near round. The cultured blister
pearls, however, typically range from
9mm through to 20mm or so.
These pearls form in the gastropod
Haliotis, which differ from the more
familiar pearl oysters in that they only
have one shell and no pearl sac.
The Haliotis Iris is also known as the Paua
shell or rainbow Abalone, and is the largest
species in New Zealand, with a maximum
shell size of around 18cm.
Other species include Haliotis fulgens,
which produce green, blue and coppercoloured
natural pearls with flecks of
fuchsia; and Haliotis rufescens – a red
abalone.
Across each species, Abalone pearls are
rarer than the more commonly known
varieties of cultured nacreous pearl.
For the gemmologist, characteristic
identifying features of the various Abalone
pearl species - besides their highly
desired multicoloured orient - includes
a botryoidal-like pattern on the surface
at magnification, and a chalky greenishyellow
fluorescent reaction under longwave
ultraviolet lighting.
Leaving nacre behind entirely, the
conch pearl proves there is beauty and
desirability in the organic nature of pearl
production, regardless of shine. Queen
conch pearls are a very rare gem that has
long been desired throughout history.
It is believed conch pearls have enjoyed
a rich history alongside their nacreous
counterparts, even symbolising a channel
of communication with gods of the sea
amongst the Inca peoples.
These white to brownish, salmon to pink
pearls are produced in the Lobatus gigas
mollusc (formally Strombus gigas) across
the Caribbean.
What these pearls lack in traditional
Abalone Pearl
Produced by the
haliotis, haliotis iris,
haliotis fulgens, haliotis
rufescens
Colour: Multiple
Found in: Australia, New
Zealand, South Africa,
Japan, North America
Mohs Hardness: 3.5
Lustre: Intense
Formula: CaCO ³
pearl lustre, they more than make up
for in the highly sought-after orangish
pink colours and a captivating porcelainlike
lustre. Conch pearls also feature
a distinctive flame-like structure that
imparts a silky appearance.
Typically, these pearls are baroque in
shape and most often between 3mm
and 8mm, with sizes surpassing
13mm being rare.
The approximate estimate of the
occurrence of gem-quality conch
pearls is one pearl in every 50,000
queen conch shells.
Pearls, in general, are always on the
more delicate side of gemstone choice,
and in the case of exotic pearls there
may be some extra precautions to take
to ensure your treasures last a lifetime.
Abalone pearls are often hollow and
therefore fragile; handle gently. Conch
pearls, on the other hand, may fade or
change colour if exposed to x-rays or
to sunlight over long periods of time.
Care should always be taken in both
cleaning and storing these organic gems.
Mikaelah Egan FGAA Dip DT
began her career in the industry at
Diamonds of Distinction in 2015. She now
balances her role at the Gemmological
Association of Australia with studying
geology at the University of Queensland.
Visit instagram.com/mikaelah.egan
For more information on gems and
gemmology ,go to www.gem.org.au
August 2022 | 39