Essentially there are three different types of pearls that you can find in the market.
We shall briefly discuss about each type of pearls in the following paragraphs.
Natural Pearls are formed when an irritant, which is usually a parasite that works its way inside a clam, an oyster, or a mussel. As a defence mechanism, a fluid will coat the irritant. There will be number of layers of this coating, known as ‘nacre’ that gets deposited until any lustrous pearl gets formed.
Any cultured pearl used for pearl necklace urban also undergoes almost the same process. Here the irritant is implanted surgically. These ‘nuclei’ or ‘seeds’ are most often created from mussel shells. Any good quality cultured pearls will need sufficient time, roughly about 3 years for a thick nacre layer to get deposited. As a result, any beautiful gem-quality pearl is formed. Lower-quality pearls are often ‘rushed’ out from oyster too quickly and have very thin nacre coat.
Pearls can either come from salt or any freshwater sources. Traditionally, saltwater pearls used to be rounder and had much better nacre than any freshwater pearls. Usually freshwater pearls are very irregular shaped, with an appearance of rice. However, improvements in farming techniques of freshwater pearl have reduced that gap.
Culturing process of pearl may take several years. Mussels should reach its mature age that may take about 3 years, which is implanted or receive naturally an irritant. After the irritant is placed, it needs another 3 years to reach to full size with proper nacre thickness. Out of the pearls created, only 5% are considered as true gem-quality to make jewellery item yet any pearl farmer will spend over $100 for each oyster which is farmed, which may not even produce any gem-quality pearl.
Imitation pearls are formed by glass beads, which are dipped into certain solution made out of fish scales. This type of coating may eventually wear out too. It is possible to identify imitation just by rubbing. Mallorca Island is quite well known for producing imitation pearl, and they are sold by using terms like “Mallorca Pearls” or “Majorca Pearls” which is frequently used to describe about these pearl simulants.