Pearl Black-Green-White Round Smooth Natural Beads Necklace 20 InchesA pearl is a hard, glistening object produced within the soft tissue (specifically) of a living or another animal, such as fossil . Just like the shell of a mollusk, a pearl is composed of (mainly or a mixture of aragonite and in minute crystalline form, which has deposited in concentric layers. The ideal pearl is perfectly round and smooth, but many other shapes, known as , can occur. The finest quality of natural pearls have been highly valued as