Thursday, April 1, 2010
How pearls are formed and their various types
A natural pearl (often called an Oriental pearl) forms when an irritant, such as a piece of sand, works its way into a particular species of oyster, mussel, or clam. As a defense mechanism, the mollusk secretes a fluid to coat the irritant. Layer upon layer of this coating is deposited on the irritant until a lustrous pearl is formed.
A cultured pearl undergoes the same process. The only difference is that the irritant is a surgically implanted bead or piece of shell called Mother of Pearl. Often, these shells are ground oyster shells that are worth significant amounts of money in their own right as irritant-catalysts for quality pearls. The resulting core is, therefore, much larger than in a natural pearl. Yet, as long as there are enough layers of nacre (the secreted fluid covering the irritant) to result in a beautiful, gem-quality pearl, the size of the nucleus is of no consequence to beauty or durability.
Pearls can come from either salt or freshwater sources. Typically, saltwater pearls tend to be higher quality, although there are several types of freshwater pearls that are considered high in quality as well. Freshwater pearls tend to be very irregular in shape, with a puffed rice appearance the most prevalent. Nevertheless, it is each individual pearls merits that determines value more than the source of the pearl.
Regardless of the method used to acquire a pearl, the process usually takes several years. Mussels must reach a mature age, which can take up to 3 years, and then be implanted or naturally receive an irritant. Once the irritant is in place, it can take up to another 3 years for the pearl to reach its full size. Often, the irritant may be rejected, the pearl will be terrifically misshapen, or the oyster may simply die from disease or countless other complications. By the end of a 5 to 10 year cycle, only 50% of the oysters will have survived. And of the pearls produced, only approximately 5% are of substantial quality for top jewelry makers. From the outset, a pearl farmer can figure on spending over $100 for every oyster that is farmed, of which many will produce nothing or die.
Imitation pearls are a different story altogether. In most cases, a glass bead is dipped into a solution made from fish scales. This coating is thin and may eventually wear off. One can usually tell an imitation by biting on it. Fake pearls glide across your teeth, while the layers of nacre on real pearls feel gritty. The Island of Mallorca is known for its imitation pearl industry.
There is no real commercial market for natural pearls. If you have a customer looking for natural not cultured pearls contact your customer reprsentive.
The difference between cultured and natural pearls is that natural pearls begin with no intervention from man.
Natural pearls are formed when a foreign object enters the shell of a mollusk and irritates the soft mantle tissue within. This irritant can be anything from a minute snail, worm, fish or crab to a particle of shell clay or mud. This object becomes trapped in a depression in the mantle tissue. This depression deepens until a pouch or sac is formed. The sac separates from the rest of the tissue and nacre-secreting cells within the sac secrets nacre over the irritant. This nacre builds up layer by layer. All of this occurs without the intervention of man what-so-ever. Most of these natural pearls are baroque - irregular in shape, either round or symmetrical. The longer the pearl remains in the mollusk, the more layers of nacre coat it. The pearl grows and so does its chance of becoming baroque.
X-ray technology is the best way to determine a natural pearl
Natural pearls today tend to be found primarily in older jewelry from estate sales, auctions, and so forth -- in other words, existing pearls rather than new ones. However, some natural pearl beds are being increasingly
The cultured pearl forms because someone inserts both a piece of mantle from a sacrifice oyster(so named because this oyster is allowed to die after the tissue samples are taken) and a nucleus ( which is most often a mother-of-pearl bead) are inserted into the mollusk. Freshwater pearls are mostly tissue nucleated only. No bead is used.
The cultured pearl forms because someone inserts both a piece of mantle from a sacrifice oyster ( so named because this oyster is allowed to die after the tissue samples are taken ) and a nucleus ( which is most often a mother-of-pearl bead ) are inserted into the mollusk. Freshwater pearls are mostly Tissue nucleated only. No bead is used.