The Nature of the Pearls
The mollusk produces a PEARL in response to a stimulus: it is, in fact, a form of defense against intrusion. This can be of natural origin, due to a small parasitic organism, or induced by man with the introduction of a foreign element inside the animal’s body springs. When the pearl is formed in response to an intrusion of natural origin, is called the natural pearl, when instead its formation is due to a human intervention, it is defined cultured pearl or cultured pearl.
The Formation of Natural Pearls
Larvae of parasitic organisms and other invaders, such as small crabs and small fish, can be introduced into the mollusk through small holes carved into the shell, or are pushed into the animal’s body by ocean currents during the power (many marine animals such as crabs, corals and oysters feed through a water filtration system extracting microscopic food particles). During the feeding phase, the hatch molluscs slightly the valves to allow the passage of water within their bodies. There are mature specimens of some large species able to filter more than 400 liters of salt water per day.
The moment any foreign element penetrates inside the body of the mollusk, causes irritation. Consequently, to defend the animal creates a sort of BAG around the intruder. The bag then begins to secrete a soothing substance, the nacre, which has the purpose of coating the irritating body. Both the fabric of the bag that the nacre is produced by the MANTLE (epithelial cells) of the mollusk (the membrane that surrounds his body and that lines the inside of the shell). With the storage area of the nacre layers irritating element, the pearl increases its size gradually.
The Formation of Cultured Pearls
As raw materials for jewelry, the cultured pearls are the result of human intervention in the process of formation of natural pearls.
Section of Natural and Cultured Pearls
Pearl Cultivation Blister
The first beads obtained in this way were the cultured pearls Blister, increased i around a core suitably pasted on the inner surface of the shell, and then extracted by means of an incision of the shell itself (this type of pearls existed for more than 700 years). The first farmers in CHINA, used to introduce small lead figurines depicting buddha as a core for the creation of blister pearls.
The first cultured pearls to form spherical, with quality Gemma, have entered the market in the 20s. These beads are coated with nacre along their entire surface and, usually, are pierced to be strung to form necklaces or for the creation of earrings, rings and pendants. They can be perfectly round, almost round or irregular.
Cultivation Of Spherical Beads
For the production of pearls “whole” there are two methods of cultivation: that with graft of spherical nucleus and that with graft tissue of the mantle.
The first is from the junction with spherical nucleus that is mainly used in shellfish with salt water. An experienced technician performs a real incision to insert the spherical nucleus and a piece of mantle tissue inside or around the gonads, the reproductive organ of the molluscs. The pearl nuclei are generally derived from the processing of the shell of a species of freshwater mussel that lives in the rivers of north america; the piece of tissue (epithelial cells play a fundamental role in the formation of the pearl) is instead extracted from a donor mollusk.
Freshwater molluscs also undergo junction with spherical nucleus, but the vast majority of manufacturers cultured pearls in freshwater prefer the method coupling with fabric that sees the transplant in a large technical fleshy area of the shellfish producer, a piece of tissue and not the pearly sphere.