Real and Imitation Pearls
The Natural Growth of a Pearl
To understand the qualities of a natural pearl, the process of its cultivation must first be understood. Natural pearls are formed within both fresh and salt water mollusks, such as oysters. Mollusks are filtered feeders that absorb nutrients from the microscopic particles and organisms in oceanic waters. To do this, they must open their shells slightly to allow water to flow in. As a result, irritants such as tiny sea animals are often caught inside their shells. In defense, the mollusk will enclose the offending irritant in a sac and proceed to secrete layers of the natural substance nacre around it, gradually creating a pearl.
Today's cultured pearls are incubated by artificial means to mimic the process that is caused by a natural irritant. Freshwater cultured pearls are nucleated with tissue, resulting in a growth pattern that is similar to that of a natural pearl. On the other hand, saltwater Akoya, Tahitian, and South Sea cultured pearls are all bead nucleated. The final result is a rounder pearl due to the nacres relatively even build-up around the spherical bead.
Imitation pearls are created to resemble natural pearls using a mixture of other materials. Ancient Egyptians made imitation pearls using a mixture of wax, quartz, powdered metals and salts. With the development of a crude glass making industry, an inner lining of foil was added to glass beads creating more sophisticated imitation pearls. To make up for weight differences, the hollow beads were then filled. In the seventeenth century, imitation pearls began to be made from fish scales and varnish. This was named essence d'orient and has been credited to Jaquin, a French rosary maker.
Todays imitation pearls vary from shell beads coated with powdered mother of pearl, to Majorica pearls where a substance similar to essence d'orient is layered over a specially prepared nucleus. The well known jewelry brand Swarovski also continues to produce high quality imitation pearls.
Testing for Authenticity
Getting your pearls X-Ray tested by a trained gemologist is the most reliable method of verifying that your pearls are genuine. In this way, you can avoid resorting to cross-sectioning, where the pearl is cut in half to reveal its layers of nacre. This presence of nacre however, can also be useful in identifying a pearl under a microscope. A natural pearl should display a slightly scaly texture on the surface as the layers of nacre overlap, or, for salt-water pearls, look for evidence of layering at the drill-hole. The outer coating of an artificial pearl will peel away slightly here.
More straightforward tests also exist for which specialized equipment and trained professionals are not needed. The quickest and simplest is the common "Tooth Test". Taking a test pearl and gently rubbing it against the surface of your teeth can reveal a fake pearl in an instant. Real pearl is formed using layers of the natural substance nacre, and will feel slightly gritty or have a sandy texture. On the other hand, a smooth surface may indicate an artificial pearl, produced using plastic or glass. A pearl should also be relatively heavy for its size and should feel just a bit cool to the touch (unless kept under showcase lights). Pearls are natural gems, so one should not look exactly like the next.
When shopping for pearls, look for a published exchange and returns policy, as well a knowledgeable sales staff. PearlsOnly.com can provide both of these, helping you to make an informed pearl selection.