This is a beautiful Pearl Necklace comprised of 73 x Cultured Brown / Rainbow Pearls roughly 7 to 8mm diameter each, fitted with a Sterling Silver bail.
A pearl is a hard glistening object produced within the soft tissue of a living shelled mollusk or another animal, such as a conulariid. Just like the shell of a mollusk, a pearl is composed of calcium carbonate in minute crystalline form, which has been deposited in concentric layers.