Pearl

Pearls are one of a few natural or organic gemstones (others include coral, amber, jet and mother-of-pearl). Produced by the pearl oyster and the freshwater pearl mussel, natural pearls are a small irritant within the oyster or mussel which has been coated with nacre to reduce that irritation. Concentric layers of nacre (composed mostly of the mineral aragonite) create the subtle iridescence and illusion of visual depth in pearls (called "pearlescence"). Metaphysically, pearls are known to enhance personal integrity, bring truth forward, grow sincerity, inhibit immodest behavior and advance in wisdom.