Pearls Part II: South Sea & Tahitian

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 Phillippines 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 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.

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