When pearls flash before the mind’s eye, what many of us think about are rows of perfectly matched, round, white pearls (likely, akoya pearls from Japan). The elegant orderliness of such a necklace has cemented its appeal for centuries. But if we look a little closer at the pearls, we might notice a subtle interplay of color. Pearls are rarely as dichotomous as white and black (Tahitian pearls being lumped into the latter). Pearl color is more often described by two components that give us near endless variations: body color vs. overtone.
The body color of a pearl is the primary or base color, caused by pigment within its composition. Akoya pearls exhibit body colors ranging from white to cream, and from yellow to silver and blue. Imagine walking into your local home improvement store and gazing up at the number of white paint swatches; the variation is staggering. So too for “white” pearls. Tahitian pearls are no different and, when observed closely, could hardly be thought of as black. A rainbow of body colors from gunmetal to grey and from green to purple are presented to the enthusiastic pearl connoisseur.
While all pearls exhibit a body color, only the finest (like those in the Spey collections) will display overtone. As opposed to pigment, overtone is a secondary color created by white light interfering within the layers of nacre that constitute a pearl, splitting the light into its component colors – a phenomenon called “thin-film interference.” This creates an aurora-like halo of color that washes across the body color of a pearl. In akoya pearls, the overtone varies from pink (the most prized) to blue and cream. Tahitian pearls display overtones of aubergine, pistachio, aqua and peacock.
Innumerable variations in body color vs. overtone (not to mention the other value factors of size, shape, surface and luster) give the fine pearl jeweler a challenge indeed. It often takes years – sometimes decades – to harvest pearls that perfectly match and complement each other within a completed strand. The result is well worth the wait. So, the next time you have your eye on a lustrous strand of pearls (we at Spey would love to have you try something on), challenge yourself to identify the body color vs. overtone. The world is your oyster, and there are many delicious things to see.
Pictured: Akoya pearls with strong blush overtone.