Pearl Luster

Pearls are formed inside the shell of some type of bi-valve mollusks such as oysters when a tiny foreign substance gets stuck inside it. These pearls are known as natural pearls. And when the foreign substance is manually inserted into the oyster, the pearl so obtained is referred to as a cultured pearl. In response to the irritation caused by the entry, the oyster immediately starts depositing layers of calcium carbonate in the form of calcite, eventually producing the pearl.

There are basically two types of cultured pearls - they are:

• Freshwater pearls
• Saltwater pearls

Freshwater pearls are the ones that come from fresh water mussels or oysters. These are mostly produced in Japan, China and the United States. Backed by a wing of the United Nations, freshwater pearls are now also being cultivated in Bangladesh.

Freshwater pearls are cultivated in lakes and rivers and a single mussel can produce up to 50 pearls. Saltwater pearls are nucleated within a small organ called the Gonad, while freshwater mussels are nucleated in the mantle tissue itself. Each side of the bi-valve mussel can easily handle up to 30 nucleations at a time.

Freshwater pearls are a delight of designers as they come in a variety of shades such as…

White, black, pink, lavender, purple and tangerine

The shades depend on the type of mussel. Freshwater pearls are also available in many shapes, including rice, button, winged, oval and flake. Insertion of slices in the mantle plays a big part in determining the size and the shape of these freshwater pearls.

However, using non-nucleus insertion method, freshwater pearls can be raised in various shapes including round, semi-round, potato, rice, short rice, long rice, water drop, flat, twin face, quad face, bread and others. With the help of Bewa Slice Insertion techniques, pearls also appear in pipa shape, long or short stick, long or short slice. Nucleus Insertion technique makes these pearls look like square, rectangle, rhombus and other interesting contours.

As these pearls usually come in smaller sizes, new technology has been developed to increase the size of freshwater pearls. It involves “Additional Planting” which is an extension of the traditional cultivating process. This technology actually uses the suspended mussel that has been raised over 2 to 3 years, and selects the finest and continuing suspended cultivation for three or more years. The process, no doubt, takes longer time but the results are promising.

The success in freshwater pearls lies in the use of graft tissue and a nucleus. Usually, the graft tissue is a portion of the mantle which is a part of the mussel that produces the shell. When a portion of this mantle is grafted inside the body of the mussel, it lives by attaching itself on the wall of the organ where it is introduced. Once there, it begins to receive nutrition and function as a part of the mantle, secreting shell substances and coating the nucleus.

And this is how freshwater pearls or cultured pearls are produced.

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