The Pearl: A Natural Wonder
Unique Among Gems
The pearl is unique among all the gemstones in the world. It is the only gem that is grown inside a living organism.
Natural pearls are formed when an irritant - a piece of shell, a scale, a parasite -- becomes lodged inside an oyster or mollusk. It forms a nucleus that is coated over several years with layers of nacre inside the oyster. The size and shape of the nucleus and the region of the ocean where the mollusk lives all affect the size, color and shape of the pearl.
Desirable Natural Pearls are Rarely Found
Today, natural pearls are quite rare. Only about one in 10,000 "wild" oysters will yield a pearl, and of those, only a small percentage achieve the size, shape and color of truly desirable gems. Most natural beds of pearl-bearing oysters were depleted by over-harvesting. However, early in the 1900s, the Japanese discovered a way to grow pearls artificially, by planting a nucleus inside an oyster and returning it to the ocean.
The Secret Behind the Pearl's Radiance
The lustrous outer surface or nacre of natural and cultured pearls is made up of the same material. Its chemical composition is about 90% calcium carbonate; the rest is water and organic materials. Pearl nacre is composed of microscopic crystals. The crystals are aligned perfectly so that light passing along the axis of one is reflected and refracted by the others to produce a rainbow of light and color.
How Natural and Cultured Pearls are Different
The key difference between natural and cultured pearls lies in the thickness of the nacre, the lustrous outer shell. To speed the growth process along, the implanted nucleus is most often bigger than the tiny grain that makes up the nucleus of a natural pearl. Even so, it takes two to three years to grow a pearl. The shape of the cultured pearl is determined by the shape and position of the implanted nucleus.
Cultured Pearls Get a Facelift
Over the last decade or so, Chinese pearl farmers have greatly improved processes for growing cultured freshwater pearls that are made up completely of nacre. The Chinese have also developed ways to reshape pearls during the growing process to result in more perfectly rounded ones. Because of that nation's large, low-wage labor force, these fine quality cultured pearls are available at unbelievably low prices.
How Cultured Pearls are Grown:
Bred for Quality
Early pearl cultivation involved planting a nucleus in wild oysters. While some seek to jump-start the natural process by implanting a tiny piece of pearl mantle inside the oyster, others use beads designed to create a larger pearl in the shortest period of time and help to control its shape. Along the way, Japanese scientists identified strains of oysters with the best pearl-bearing qualities and focused on using them to produce pearls of high luster and clear, uniform color.
Enter the Nucleus
Technicians open the live pearl oysters gently, then surgically implant a small polished shell bead and piece of mantle tissue in each. The shell bead is the nucleus around which the oyster secretes layer after layer of nacre, the crystalline substance that forms the pearl.
Back to the Sea
Nucleated oysters are returned to the sea, where they are suspended from rafts in sheltered bays rich in natural nutrients. The oysters will feed and grow, secreting lustrous layers of nacre around the implanted bead. In winter, the oysters are moved to warmer waters. Pearl technicians monitor water temperatures and feeding conditions daily at various water depths and move the oysters to take advantage of the best growing conditions.
Pampered Oysters
The pearl-bearing oysters are lifted from the sea for cleaning and health care. Seaweed, barnacles and other growths are removed and the shells are treated with compounds to prevent parasites from injuring the oysters.
The Birth of a Pearl
Typhoons, red tides of plankton and predators all take their toll before the pearls are ready to be harvested. On average, about half of the nucleated oysters do not survive to bear pearls. Millions of oysters are nucleated every year, but only a fraction live to bear pearls. Less than five percent of nucleated oysters yield pearls with the ideal shape, luster and color to be considered fine gem quality.
Care For Your Pearls
Pearls are soft compared to other gemstones and precious metals. It is important to take special care of your pearls to ensure they will remain bright and beautiful for generations to come.
Personal Care Products Can Damage Pearls
Cosmetics, perfume and hair spray all contain chemicals that can dull the luster of a pearl. The natural acids contained in body oils and perspiration can damage pearls in the same way. It is best to put your pearls on after applying makeup, perfume and hair spray.
Simple Steps to Protect Your Pearls
Wiping the pearls with a soft damp cloth after you wear them will ensure that they remain free from harmful build-ups of these compounds. Periodically, pearls should be washed with a mild soap.
Store Pearls Separately from Other Jewelry
Always keep your pearls separated from hard jewelry items, to prevent them from being scratched. Pearls are best kept in a soft cloth pouch or a soft lined jewelry box or compartment.
When to Have Pearls Restrung
If you wear your pearls often, they should be restrung about once a year to prevent strand breakage. Experts suggest the use of silk thread. However, nylon thread is an acceptable alternative. The string should be knotted between each pearl to prevent all the pearls in a strand from falling off should a break occur. Knotting also keeps the pearls from rubbing against each other.
Information From:
pearlparadise.com
For More Information, go to:
http://www.shaneco.com/jewelry/pearls.asp
