Pearls Essays - Pearls, Pteriidae, Bivalves, Gemstones, Pearl

Pearls What is a pearl? A pearl is a pellet of calcium carbonate. Of all the gems in the world, it is the only one created by a living creature. A pearl is found in an oyster or other mollusk. They are grown in limited areas of the worlds oceans and come in wide range of shapes and colors. The value of a particular pearl is determined by a number of factors. The prices of these precious stones are widely varied depending on the perfection of the stone. A pearl is a very unique, valuable gem. Pearls were first introduced in the 1850s when they were discovered in Western Australias Shark Bay. Here the gems were found in the salt water albina oyster, known as Pinctada. In the 1880s the pearl industry rapidly spread along the north west coast of Australia. By 1910, nearly 400 luggers and more than 3500 people were fishing for shell in the waters around Broome, then the biggest pearling centre in the world(Western Fisheries Australia). During this time, the luggers were powered by sail and only equipped to carry the apparatus for one diver. The divers wore vulcanized canvas suits, lead-weighted boots, and enormous helmets made of bronze while they collected shell underwater for hours at a time. The 1930s improved upon the vessels. They were now motorized and had mechanical air pumps that could support two divers per boat. The early pearl industry had an alarming death toll of approximately 300 men. Cyclones and sharks mostly caused the deaths. Between the 1920s and 1940s the pearl industry nearly crashed due to the increasing use of new plastics for buttons, buckles, and other shell products (Western Fisheries Australia). The introduction of cultured pearls revived the pearl industry in more recent years. Pearls are the product of several mollusks. They are usually found in the salt-water species known as Pinctada. There are two ways that pearls are formed. They can be man made or naturally made. Natural pearls are formed when deposits of nacre around an irritant accidentally settle within the flesh of an oyster. Pearls that are produced with the help of man are called cultured pearls. These pearls are created in an oyster and are composed of concentric layers of a crystalline substance called nacre that is deposited around an irritant placed in the oysters body by man (Kelley Jewelers). Cultured pearls are produced on oyster farms, where the mollusks are grown to the age of three. At this age, they are removed from the sea and have pegs placed in their shells to keep them open. The nucleus and a small portion of the nacre-secreting cells are then placed in a tiny incision made in the body of the mollusks. Finally, the pegs are removed and the oysters are returned to their cages in warm waters. The oysters will grow in the cages for two to four years before the pearls are ready for harvesting. Size, weight, and color assort the harvest (Pick a Pearl). There are many different colors, sizes, and types of pearls on the market today. White, cream, pink, green, blue, and black are recognized as the seven acceptable colors by the pearl industry (Pick a Pearl). The industry also acknowledges several different types of these precious stones. One type is the Akoya, which is the most common cultured pearl. It is grown off the coasts of Japan in pearl oysters. It rarely grows beyond nine millimeters in size. Another pearl that is cultivated in Japan is the Biwa. It is only grown in the fresh water of Japans Lake Biwa in mollusks, not oysters (Kelley Jewelers). Some larger cultured pearls are the South Sea and Burmese. South Sea pearls are very rare and expensive. They are found of the coasts of Australia and have a metallic bluish-black color. They are much larger in size compared to the Akoya. South Sea pearls are normally ten to twenty millimeters in diameter, with a harvest average of about thirteen millimeters (Anderson). The Burmese pe arls are produced off the coasts of Burma. They too are rare and expensive. A Mabe pearl is large in size and has a hemispherical shape. It is less expensive and is