Back to Basics: What is Mother of Pearl?

June 17, 2015 by Melissa

Many people would recognize mother of pearl when they saw it, but how many of us actually know what mother of pearl is, where it comes from or how it is made? Or, more specifically, how many know the difference between mother of pearl and a pearl?

Unsurprisingly, pearls and mother of pearl are made of the same substance: nacre, an iridescent material composed of calcium carbonate. Nacre is created by mollusks to protect their soft interior tissue. The difference between pearls and mother of pearl is placement. Mother of pearl is created on the inner linings of a shell. A pearl, on the other hand, is created when a foreign object enters the shell and the mollusk encases the foreign object in order to protect itself. The material used to create the encasement is the same nacre, or mother of pearl, material discussed above. The end result of this foreign object being encased in nacre is a round-shaped pearl, whereas mother of pearl takes the shape of the shell that it lines.

Have you wondered about the source of mother of pearl’s iridescent appearance? The answer is in the nacre material itself, which is secreted by the epithelial cells. The epithelial cells secrete thin platelets, or building blocks, of nacre. The thin platelets of calcium carbonate secreted by the mollusk to create the mother of pearl inside the shell have a width which matches that of many light waves. This is what gives mother of pearl the beauty which makes it so sought after in the creation of everything from jewelry to watches to furniture.