What Is a Pearl?

A pearl is one of the few gemstones classified as “organic” (it came from something alive-a live mollusk) and because of its organic nature, it is one of the most beautiful and expressive gems in the world. Pearls are produced without help (native or wild) or with help (aquaculture) by many different species of mollusks (oysters, clams, conchs and mussels) in both salt and fresh waters.

“Real pearls” or “genuine pearls” are either formed or farmed, with natural or wild pearls being pricier than farmed or “cultured pearls.” And yet both methods are “natural.” Mollusks naturally produce pearls in a large range of colors, among them: white, eggshell, off-white, taupe, beige, brown, gold, copper, purple, pink, blue, gray, silver and black.

But what makes pearls so special is their organic nature. Chemistry sheds light on, but in no way explains the look of a pearl. A mollusk secretes a substance called nacre, which is made of calcium carbonate to form its hard chalky shell. But open a sea shell or mussel and you will see a shiny rainbow of colors refracting and reflecting from the inner surface because the mollusk protects itself from its rough outer shell by lining its home with these layers of nacre (or mother of pearl.) When nacre is secreted in many layers around a bit of grit or an implanted piece of shell, or a bead, the result is a pearl, which has the same luster as the shell’s inside.

The reason for this luster is that in between the calcium carbonate layers the mollusk secretes a mixture of proteins which not only make the inside of the shell strong and slippery and more comfortable for the mollusk, they make translucent layers on the pearl that trap water. When light penetrates these layers it disperses and refracts, causing the shimmering display of soft glowing colors we see when we look at a quality pearl. And let’s face it, this unique variability makes them charming, gorgeous next to the wearer’s skin, and just plain classy.

Next Post:  How to Tell the Value of Pearls-Shell Time


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