A genuine pearl has a distinct pearl brilliance and a natural, rough texture. This is due to the fact that it has microscopic ridges on its surface. These ridges may be imperceptible to the naked eye. Experts and jewelers, on the other hand, can use a magnifying lens to examine the "natural faults" in a pearl. They believe that this gives pearls a more distinctive look and also makes them more valuable. Pearls are formed when an oyster deposits a nugget of calcium carbonate into a special gland within its mantle. The pearl grows over time until it's large enough for the oyster to die. At this point, it releases the pearl from its body. It is then ready to be harvested by someone who knows how to find them. Although they are beautiful and valuable, not all pearls are equal. There are two main types of pearls: cultured and wild-caught. Wild-caught pearls are found on dead shells or discarded fish nets and have not been treated with chemicals. They tend to be smaller and less valuable than cultured pearls. Cultured pearls are produced in factories where workers clean the shells and apply chemicals to make the nacre (the layer of mother of pearl inside the shell) softer so that it can be separated from the shell. This process removes the death nail (a remnant of the former life of the shellfish) while leaving the pearl intact. It can then be sold individually or as part of a stringed jewelry collection.