Although they come in a variety of colors--pastel, black, blue, gold--and shapes that range from spherical to teardrop, the most popular pearls are the small, spherical balls that have immortalized the stone as a sign of sophistication and understated class. Their appearance invokes in them a sense of purity, and variations on that theme, including wisdom, integrity, modesty, and self-worth. Most significantly, their association with loyalty is likely the reason they’re so popular with brides. The value of pearls is also dependent on whether they are found in nature or cultured--that is, created using a farming technique (although still natural). The former is, understandably, much more valuable given their rarity, and can fetch up to hundreds of dollars per pearl.