Pearls are created by living creatures called molluscs. Although all molluscs which produce a shell can produce a pearl, naturally occurring pearls are still very rare – found in perhaps one of every 10,000 animals.
As products of living animals, pearls are unique among gems. Depending on fashions and tastes, the most sought after pearls may be perfectly round, pear-shaped or irregular. With their long history and amazing qualities, pearls are more popular than ever now.
The term Akoya refers to nucleated saltwater pearls cultivated in the Akoya oyster. The first pearls were cultured in Japan, where the techniques for growing pearls were developed about a hundred years ago.
The majority of Akoya pearls harvested are round in shape. However, other shapes like baroque, button, oval, drop etc. can also be found.
The base colours in Akoya pearls are primarily white, cream and yellow (often with a greenish overtone, sometimes with a grey but seldom with a pink or rose). There are no natural black Akoya cultured pearls, and only a small production of natural blue or grey pearls.
White South Sea Pearls
White South Sea Pearls refers to pearls grown in the southern ocean, mainly off the coast of Western Australia, Indonesia, the Philippines and Myanmar. They are grown in the Pinctada Maxima oyster which is the biggest oyster of all species (size 20-30cm).
Pearls produced range in size from 9 to 18mm (occasionally bigger). The largest cultured
White South Sea pearls come in a variety of colours, ranging from white through to silver blue, and from cream to golden colours.
Black South Sea Pearls
Black South Sea pearls are cultured using a species of oyster called the Pinctada Margaritifera or “black-lip” oyster. This variety of mollusk is indigenous to the lagoons and the atolls of French Polynesia.
Tahitian oysters love the pristine lagoon waters, where temperatures range between 24-29 degrees. At 18 degrees, it stops growing, and at 11 degrees, it dies.
As with other South Sea pearls, the Tahitian pearl ranges in size from 8-16mm (sometimes bigger).
Colours of Tahitian pearls range from gold through greens to aubergine or purple, and to quite a dark black. Generally, the darker the pearl, the more valuable it is. True peacock black pearls are typically expensive.
Shapes come in round (only a limited percentage), oval, drop, button and baroque. A significant amount also come in circles.
Freshwater pearls grow in a mussel species (Hyriopsis Schlegeli). The mussels are not rare and are mainly found in rivers, lakes and ponds in China and Japan, and also in Europe, Russia and America.
The pearl grows up to any possible size, depending on the number of years the oyster is left in water. In this case, the pearl produced has no nucleus inside. A Freshwater mussel can produce up to 50 pearls at a time.
Almost all Freshwater pearls are cultivated. Non-cultivated Freshwater pearls are very uncommon.
Freshwater pearls have an endless variety of shapes, sizes and colours.
The word ‘Keshi’ means ‘poppy seed’ in Japanese and these pearls are also sometimes referred to as seed pearls.
There is considerable controversy as to the classification of whether Keshi pearls are natural pearls or cultured pearls. It is impossible to determine the difference in the laboratory.
As a basic rule, if the oyster has been seeded by human intervention and an additional pearl (by-product) is created through the provocation of any substance, the pearl is considered to be cultured and is therefore called a “Keshi” pearl and is 100% nacre.
They are generally small in size and their shapes vary widely. Keshi come in a wide variety of colours and tend to have a high lustre. Most common today are the South Sea and Tahitian Keshi pearls.