Pearl color is a key factor to understand when buying pearls. We're here to give you the inside scoop on how a pearl acquires its natural color. Pearls come in a rainbow of natural color from classic white to black to blue and even violet! So where do these colors come from?
Pearls Come in Every Color of the Rainbow
Often pearl color is influenced by the color of the mollusk’s lip, the outer part of the shell. For instance, Tahitian pearls get their light to dark charcoal grey colors from the black-lipped saltwater Tahitian pearl oyster, Pinctada margaritifera. Notice the grey to silvery hues present on the edge of the shell.
Tahitian Shell Iridescence
Another way pearls get their color is from microscopic pigments inside the conchiolin layer. Conchiolin is the organic “glue” that holds the crystalline aragonite layers together. Conchiolin cements these platelets together (think of the structure of a pearl as something like a brick wall, and the conchiolin is the cement).
Nacre Layers Under Magnification
When the conchiolin is pigmented with grey, brown, reddish-brown, black or other colors, this pigment shows through the thin crystalline layers to give the appearance of blue, grey, yellow, green, bronze, black pink and orange hues in the surface of the pearl.
Aragonite Platelets in Pearl Nacre
Lastly, aragonite platelets are the semi-transparent, hexagonal-shaped, microns-thin crystals that make up the prismatic layers of the pearl. When white light strikes and penetrates the surface of the pearl and its layers, the light beam is refracted back at the viewer in its entire spectrum, allowing the viewer to see the colors red, orange, yellow, green, blue and violet. This phenomenon also heavily influences the pearl’s overtone, or faint iridescent colors that are visible over the body color of the pearl.
Golden South Sea Pearls. Left: Medium Golden Tone with Light Rose Overtones Right: Deep Golden South Sea pearl with Bronze and Green Overtones.
As you can see, each of the Golden South Sea pearls above displays varying shades of Golden body color intensity, however the overtone or faint iridescent color lying over the main body color influence the pearl’s overall color to the viewer. The pearl on the left shows a faintly blushing “warm” tone due to its Rose overtones, while the pearl on the right appears much “cooler” due to its Green and Bronze overtones.
While the science of pearls is still evolving, we now have a fairly good idea of how a pearl’s color is influenced both by its environment and by the host mollusk. I hope this you found this blog post as fascinating as I did writing it - the science of pearls and their unique colors continues to astonish and amaze …
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