A pearl is a hard object produced within the soft tissue (specifically the mantle) of a living shelled mollusk. Just like the shell of a clam, a pearl is composed of calcium carbonate in minute crystalline form, which has been deposited in concentric layers. The ideal pearl is perfectly round and smooth, but many other shapes (baroque pearls) occur. The finest quality natural pearls have been highly valued as gemstones and objects of beauty for many centuries. Because of this, pearl has become a metaphor for something rare, fine, admirable and valuable.
PRIMARY GEMSTONE: An organic gem made up of calcium carbonate (CaCO3) has the same chemical composition as that of tooth and our nails. Pearls have a hardness of ‘2.5’ to ‘4’ on the Moh’s scale of hardness this are quite soft. The other physical properties of Pearls include a refractive Index of ‘1.530-1.685’ and moderate specific gravity of ‘+/-2.70’.