Mother-of-pearl or Nacre is the substance that constitutes the inner part of the shell of certain mollusks, its name comes from the Latin “ nacrum “, which was used to describe white matter with iridescent reflections.
It consists of a mineral part of calcium carbonate crystals in its aragonite form and an organic part called conchiolin, which represents only 4% to 6% of the nacre but can assemble all the aragonite crystals in a solid matter. It is the light diffraction on,the aragonite microcrystals that causes the iridescence.
The color of the nacre depends on the mineral ions or substances present in the environment in which the mollusk lives, the carotenoids type of organic pigments in the conchiolin contribute to the orange-yellow to purple coloration.
A very colorful nacre and multicolored in green and blue, that comes from the abalone (Haliotis australis) of New Zealand was already used by the Maori … this variety of nacre is often called “sea opal”, even if it has nothing in common with the opal.