Pearl 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.
Moonstone is a sodium potassium aluminum silicate. Its name is derived from a visual effect, or sheen, caused by light diffraction within a microstructure consisting of a regular succession of feldspar layers. It is composed of two feldspar species, orthoclase and albite.