Jeweller - May 2022

Pearls Part II: South Sea & Tahitian
Above: Autore Pearls; Arosha Taglia
Below: Assael pearls; Musson
South Sea and Tahitian pearls are the most
prized of pearls cultured today. These
exceptionally lustrous beauties can only
be grown with meticulous care in the most
pristine environmental conditions.
The term South Sea pearls, by CIBJO
definition, refers to cultured pearls from
a Pinctada maxima oyster, grown in the
Indian and Pacific oceans off the coasts
of Australia, Indonesia, the Philippines
(these being the most significant
producers), and Myanmar.
Compared to the saltwater cultured
Akoya pearls (to be explored in Part III),
South Seas have a particularly thick
nacre and distinctive lustre.
The classic white is in the highest
demand of all colours possible in South
Sea pearls, with appreciation growing
for the rarer golden tones. The specific
oyster in which these pearls are grown
determines the resultant colour.
The silver-lipped (or white-lipped) variety
that produces the famous white pearl with
a silvery overtone inhabits the waters off
northern Australia and southern Indonesia,
below the equator. Other colours can
include pinkish and bluish overtones.
Above the equator, the gold-lipped (or
yellow-lipped) variety occupies the
waters surrounding the Philippines and
Indonesia, though also in Myanmar. As
the name suggests, the champagne and
creamy colours this variety produces
can also extend to the rarest of colours -
impressively saturated golden hues.
Of all cultured pearls collectively, the
South Seas are the largest. The average
South Sea pearl will take around
four years to grow, though this varies
as more time is needed to produce
larger pearls. Their size ranges from
approximately 8mm to an outstanding
22mm. These larger specimens are
scarce and valuable.
Heading east and further out into the
South Pacific Ocean, Tahitian pearls
– as they're known – are cultivated
around the islands of French Polynesia.
CIBJO defines these as cultured pearls,
naturally coloured, grown in a natural
environment around these islands by
the Pinctada margaritifera cumingii
oyster. This oyster is black-lipped, and
hence the pearls that result include a
variety of cool hues.
Sometimes referred to as 'black pearls' or
even 'black South Sea pearls', the range
of colour seen in Tahitian pearls is much
more extensive than these names suggest.
Primarily shades of grey, brown, and black,
the possible overtones include blues,
greens, pinks, purples, and even creamy
yellows that give some fantastic colours.
Some popular names adopted by the
trade for Tahitian pearl colours are
'pistachio', 'aubergine' and 'peacock'.
The true black peacock pearls are rare
and carry a price tag to reflect this.
Tahitian pearls are similar to South Sea
South Sea &
Tahitian Pearl
Produced by the
Pinctada maxima and
Pinctada margaritifera
oysters
Colour: Multiple
Found in: Australia,
Indonesia, Philipines,
Myanmar
Mohs Hardness: 2.5 - 3
Lustre: Pearly
Formula: CaCO ³
pearls in size, typically ranging from
9mm to 18mm.
Being gems of an biogenic nature,
a particularly brilliant feature of the
pearling world is the positive impact on
conservation. As they require pollutionfree
waters and thriving ecosystems to
produce gem-quality pearls (which, even in
ideal conditions, is a small percentage of
production), the industry promotes healthy
and sustainable oceanic environments.
As is possible with all pearls, various
treatments can be seen in South Sea
and Tahitian pearls. Dyes, coatings,
lustre enhancements, waxing, and
chemical alteration are just some
potential treatments, all of which
require disclosure upon sale. Features
like uneven colour, unusual blemishes,
discrepancies in fluorescence, and a
waxy-look lustre, can all assist in flagging
possible treatment. However, it is not
always possible for gemmologists to
discern treatment without advanced
laboratory equipment.
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
May 2022 | 37