Pearls have been known since ancient times as the Queen of gems, this may seem strange to us now since they are much softer and far less durable than most other true gems such as diamond, sapphire and ruby.
however it is the only gem which does not have to be cut or polished to reveal it's inner beauty.
Nature presents us with the finished article, an organic gem of great beauty.
Natural Pearls.
Everyone knows pearls are found in oysters but it is not the oyster we order in a fine restaurant, there are many other species of oyster.
These molluscs can be divided into:- 1.
Saltwater oysters which live in the seas and oceans.
2.
Freshwater mussels and oysters which live in lakes and rivers.
The body of an oyster is soft and vulnerable, hence it`s strong shell.
Inside the shell the oyster secretes a layer of mother of pearl which provides a smooth surface for the oyster.
Sometimes a piece of grit or a parasitic worm may get into the oyster and cause it irritation.
The natural response is to cover this intrusion with a layer of pearl nacre, the same substance that forms the smooth mother of pearl layer in the oyster shell.
Layer upon layer of nacre is secreted onto the pearl and over the years it increases in size, not always to form a spherical bead but usually to produce an unusual shape or what is known as a baroque pearl.
The oysters live in oyster beds at the bottom of the sea and have to be brought to the surface by divers, only a small proportion of the oysters contain pearls.
Traditionally they were found in the Red Sea, the Persian Gulf and the Gulf of Mannar off the north west coast of Sri Lanka.
Other pearl fisheries are; north-west coast of Australia, of the coast of southern Myanmar, the Sulu Sea, of the coast of New Guinea and Borneo, the Gulf of Mexico, and Gulf of California, of the coast of Venezuela and Tahiti.
Freshwater pearls are found in the rivers of the United Kingdom and in rivers in the U.
S.
Today many of these natural pearl fisheries have been exhausted or the dangerous and arduous work of pearl fishing is no longer attractive to the local population.
Cultured pearls The supply of natural pearls was becoming scarce in the 1920`s when cultivated pearls started to appear on the market.
In 1921 after many years of experimentation Mikimoto a Japanese scientist and business man started to distribute his pearls.
This was the first time spherical cultured pearls had appeared.
Mikimoto was not the inventor of the process, many hundreds of years earlier the Chinese had found that objects placed in oyster shells would become covered in pearl nacre.
They placed tiny metal statues of the Buddha in oysters and the oyster then obligingly covered them in mother of pearl to produce beautiful little ornaments.
The Japanese developed this technique taking many years to perfect it to produce spherical pearls.
A part of the oyster called the mantle contains cells which secrete crystalline calcium carbonate, this is what pearls are made from.
A small sac of mantle is cut from a live oyster and a mother of pearl bead inserted into it.
This is then placed in the mantle of a mature three year old oyster by means of an incision with a scalpel.
The incision is closed by a ligature, the process is antiseptically treated before the oyster is returned to the sea.
The oysters are kept in cages for several years before being retrieved.
When the oysters are fished up the mother of pearl bead is found to be coated with layers of pearl nacre just like a natural pearl.
This was the original technique, today other more efficient methods are used.
Essentially it means that cultured pearls have a mother of pearl bead inside them with a varying thickness of layers pearl nacre surrounding it.
While natural pearls are composed entirely of concentric layers of pearl nacre.