princess_diamond_wedding_ring

Another unique aspect of the pearl is the fact that it is the only gem that does not need to be cut and polished, but for certain items the pearl needs to be drilled or partly drilled. Indeed its natural lustre is so remarkable that it can often be taken straight from the shell for use in jewellery.
The pearl-producing oyster is a soft-bodied animal, more like a scallop than an edible oyster. It belongs to the Bivalve group of molluscs and the name means, simply, double-shell. Nature uses this shell to protect the soft mantle of the animal. Sometimes a sharp fragment penetrates the shell, like a grain of sand, a piece of broken shell or even a shell-boring animal. Consequently an irritation is set up and in an attempt to ease this annoyance, the oyster covers the irritant with a mother-of-pearl type substance, called nacre. The whole of the irritant within the tissue is completely enveloped. The oyster continues to add layers of this nacre, so that the more layers there are, the larger the pearl.