Pearl Nacre
Nacre, also known as mother-of-pearl, is a crystalline substance that creates the iridescent visual effect attributed to pearls. Nacre is an organic substance secreted by molluscs over an intruding irritant or implanted nucleus. It is a strong and resilient material that is lightweight and transparent, allowing light to pass through its surface, creating a subtle glow on the pearl’s surface.
Since nacre determines lustre, nacre quality is a critical factor when determining a pearl’s value. Generally speaking, the thicker the nacre, the more valuable the pearl. Thick nacre not only looks better than thin; it also is much more durable.
Freshwater Pearls are of Solid Nacre
Freshwater Pearls differ from other cultured pearls, in that the great majority of them are not bead-nucleated. Freshwater molluscs are nucleated by introducing a tiny piece of mantle from a shell, which causes the formation of a pearl sac, where the tissue deposits calcium carbonate.
The resulting pearls are of solid nacre, but without a bead nucleus to guide the growth process the pearls are rarely perfectly round.
