There are myriad theories as to how the horseshoe came to be a symbol of good luck. One of the most compelling theories is that the horseshoe evokes the shape of a crescent moon, which many ancient cultures believed to influence the bounty of crops and effect the events of everyday life. Amulets in this shape such as animal horns, the mano cornuto (the sign of the horns co-opted by 20th century metalheads, but originally used as early as Ancient Rome as anti-witch gesture and/or talisman), and yes, also the horseshoe, have been used the world over as a protection against the evil eye and bringer of fortune. Another interesting postulate is that it's not the shape, but rather the metal itself (iron) that works to protect the wearer or dwelling where it is employed. Pliny the Elder wrote that iron nails hammered into the doorway of a home would guard against night spirits. In Arab mythology, the demons known as Jinn could be exorcised by merely speaking the word "iron". Whatever the explanation, across centuries and cultures, the horseshoe is widely believed to be a bringer of luck. This Edwardian horseshoe ring is fashioned in 18k yellow gold with a lucky 7 rose cut diamonds.