Australian south sea pearls

A pearl is a natural gem created by a living organism. When a foreign object is introduced into a mussel or oyster the animal coats the irritant with a substance called nacre, the same material with which it builds it's shell. Layers of nacre build up to make a pearl.

More information can be found on pearl formation on www.gia.edu.

Strands made of Australian South Sea Pearls up to 15mm are often put together from one harvest. Exceptional strands often take three or more harvests. Some have taken much longer. But the answer is not so simple, because we have been stocking our large pearls for at least the past 10 years to enable us to assemble strands in these sizes. So it is possible that a strand has one pearl from harvest 2004 and another from harvest 1994.

The farms are dotted along more than 2,500 kilometres of coastline – from the Cobourg Peninsula to Exmouth on the north-west Australian coast. An equivalent distance to from London to Moscow! This coastline is in the heart of North Australia’s cyclone belt which annually faces the world’s fiercest tropical storms – a management task in itself to ensure the ongoing viability of the pearl project and the safety of the workers who tend the oysters daily throughout the year.

Kuri Bay’s history extends to the post-war resurgence of the pearl coast. This remote settlement was founded in 1956, as Australia’s (and, indeed, the world’s) first South Sea pearl farm.
 Kuri Bay was named for Tokuichi Kuribayashi of Nippo Pearl, the company that provided the technical expertise for this early farming joint venture.

Lustre, Complexion, Shape, Size, Colour.

Approximately 3-4 years before the first operation.

Annually from May to September.

It varies depending on the size and health of the oyster. More important is the nacre thickness. Akoya pearls have a nacre thickness of only around 0.1mm, whereas on a 13mm Australian South Sea pearl the average is 2-4mm.

The best nucleus is made from 100 per cent hand-selected Mississippi clam shell. Ongoing research provides unequivocal evidence that the Mississippi clam shell produces the best results, sharing the specific gravity and almost identical composition to the nacre of the Australian South Sea pearl, ensuring an end product of the highest quality and durability. It is common for Chinese Freshwater pearls to use a lower grade material, such as plastic, for the nucleus.

Approximately 800 employees currently work across the pearl production divisions of the business.

Each oyster is cleaned by hand at least once a month – at slightly shorter periods during the Dry season and longer periods during the Wet season.

Generally an oyster is seeded only the one time, occasionally twice and rarely a third time.

Australian South Sea pearls grow over a 2-3 year period. Other South Sea pearls grow over 1-2 years, and Akoya pearls take only 6 months (on average) to grow.

Bigger than a dinner plate; approximately 50 years of age.

The durability of all pearls cannot be described as if all pearls are homogenous; e.g. untreated pearls are much more durable than treated pearls (treatments are processes such as dyeing, bleaching and enhancing lustre by chemical treatment).


Akoya pearls are generally the most fragile and least durable of all cultured pearls due to their thin coatings of nacre. Akoya pearls are also almost always treated in some way. As a point of reference, an Akoya is deemed to be good quality if its nacre is 0.15mm thick. Good quality Australian South Sea pearls have on average at least 2mm of nacre. The natural pearl nacre of Australian South Sea pearls will respond well to body oils, etc. Being made primarily of calcium carbonate, it is softer than diamonds and will react adversely to acids which destroy calcium carbonate – as would our teeth.

The world’s jewellery market is dominated by gold, silver, and diamonds, with pearls representing only 2% in value of total jewellery sales. Cultured Australian South Sea pearls account for just 1% in volume of the global production of all cultured pearls, yet they account for nearly a third of the value. This obvious preference for quality has increased the demand for high quality pearls worldwide, thus pearls of a certain quality will remain scarce, as increases in production take years in lead times, and quantities cannot be easily or cheaply increased by alternative sources.

While natural Australian South Sea pearls are rarely found in the wild today, cultured pearls are virtually indistinguishable from their natural ancestors.

Only Nature can decide what shape and colour a pearl will be. While the small nucleus or seed implanted in a pearl oyster is round in shape, due to the thickness of the South Sea oysters’ nacre, the pearls emerge in a wide range of shapes. Symmetry is rare in nature, and therefore round shapes are the most highly valued. See The Five Virtues for an explanation of the variety of Australian South Sea pearl shapes available.

Also known as 'mabe' or 'cultured blisters', the cultured half-pearl is initiated by attaching a hemispherical nucleus on the inside lip of the shell. As the oyster grows and secretes its pearl nacre, the half-pearl grows into a domed blister which is later removed from the shell and backed with mother-of-pearl.

'Keshi' is a Japanese term which relates to 'small' pearls. They can be either natural or cultured. They can have a solid nucleus (such as a grain of sand), a soft nucleus (such as a small piece of organic material), or a hollow centre, but never an implanted nucleus. As they are impossible to differentiate by eye, all keshi pearls are classified as cultured, unless they are examined by x-ray and accompanied by a certificate from a reputable gemmological laboratory. They generally range in size from 2–10 millimetres and remain quite rare.

The colour of South Sea cultured pearls is determined only by nature and can be any of the colours of the mother-of-pearl oyster in which it forms. The finest Australian South Sea pearl oysters can display a magnificent array of all the colours of the rainbow, and as such, Australian South Sea cultured pearls are found in a myriad of colours from golds though to silvers and, of course, white. Pearls may also have many different coloured overtones, which sometimes combine with a translucent lustre to produce the effect known as orient.

A South Sea pearl is produced by the Pinctada maxima - the largest of the pearl-producing molluscs. They are mainly produced in Australia, primarily with wild oysters, and in Indonesia and the Philippines with hatchery-reared oysters.