Difference Between

Freshwater vs Cultured Pearls

Pearls are objects of beauty and used as jewelry by women all over the world. Pearls are produced naturally by sea creatures such as mollusks. Pearl is developed when a foreign object (normally sand particles) gets trapped between its mantle folds and gets converted into a hard, round, shiny object that is treasured by human beings since ages. While there are oysters producing pearls that live in seas, there are other creatures such as mussels that live in freshwater and also produce natural pearls. Natural pearls are rare and valued highly. Considering their high demand, pearls are these days being cultured that is being produced by human intervention. There are many countries that export huge quantities of cultured pearls and China and Japan lead such countries. There are many differences in natural freshwater and cultured pearl that will be discussed in this article.

The value of pearls depends upon their luster, roundness and smoothness apart from other physical properties of reflection, refraction and diffraction of light through their layers. Pearls are made up of thin overlapping layers that aids in breaking up light falling upon its surface. A pearl is the result of a defense mechanism that is adopted by the creature to defend itself from a foreign object that enters its mantle folds. This foreign object could be a parasite or just sand particles but the creature produces a sac and traps this foreign object inside it and this sac later turns into a pearl.

Cultured pearls are a result of humans trying to put an irritant in the mantle tissues of the mollusk when it opens its shell valves for breathing or feeding. In case of freshwater pearls, mollusk produces calcium carbonate and conchiolin to cover the foreign particle that causes irritation. These materials are secreted over a period of time forming layers over the foreign material.

In the case of cultured pearls, a tissue from the mantle of a donor shell is implanted on the mantle of the recipient that produces calcium carbonate over this piece of tissue and transforms it into a pearl. Though it is difficult to tell the difference between freshwater and cultured pearl with naked eyes, when X-rays are passed through these pearls, the truth is revealed. Both have different structures with cultured pearls having a solid center with no concentric rings. On the other hand, natural freshwater pearls are conspicuous by the presence of concentric growth rings around the center.

Before cultured pearls arrived, natural freshwater pearls were valued highly, but their value fell with the introduction of cultured pearls that could be produced in many different colors. When you are buying pearls, beware of cultured pearls as many of the so called natural pearls today are in reality cultured pearls.