Tissot Ladies Watches Le Locle Automatic T126.96.36.199 - AAThe mantle senses the grit as an irritant and its defense mechanism reacts by producing a layer of nacre to cover up the piece of irritant. As the oyster grows, more layers of nacre are formed over the grit.Nacre is iridescent and this is what makes the pearl a beauty to look at. The luster of a pearl depends on the quality of the nacre, mainly its thickness. Not all pearls are round. Some come in uneven shape. They come in various colors like white, blue, green, gray, pink, purple and black Tissot Ladies Watches Le Locle Automatic T188.8.131.52 - AA. The rarer the color, the more expensive it is.Black pearls are rare and are mainly found in the small islands of French Polynesia. Among the group of islands, Tahiti is the main island and the center of commerce for pearls. Due to this, black pearls are often referred to as Tahitian pearls. In this region, pearl cultivation takes place in oyster farms which are mainly closed lagoons mainly located on the islands to the west and east of Tahiti.
Pearls have been the object of beauty for centuries and natural pearls have been worn by royalties and the rich in the past. They are mainly formed by oysters although clams and mussels are able to produce pearls too, but this is very rare Tissot Ladies Watches Le Locle Automatic T184.108.40.206 - AA. Most pearls sold today are of the cultured type cultivated in farms. Natural pearls, which are formed by oysters in the seas, without human intervention, are very rare. About one in every ten thousand oysters may produce a pearl and this resulted in wild oysters being hunted into near extinction in many parts of the world.A pearl is formed when an outside object, like a tiny grit, enters the oyster when the shells are open, into a position between the mantle and the shell. The mantle is an organ inside the oyster that produces the substance called nacre that forms the shiny inside layer of an oyster shell Tissot Ladies Watches Le Locle Automatic T220.127.116.11 - AA.