Technically known as Staurolite, a Fairy Cross or Fairy Stone is made up of iron aluminum silicate crystals.
Usually the twin crystals form the shape of a cross – either 90o or 60o. But you can find Staurolite crystals with both at 60 degree and 90 degree crystals: these look more like a six-rayed star than a cross and are much rarer.
The legend of Fairy Crosses goes that when the fairies learned about Christ's crucifixion, they cried. Their tiny tears fell to earth. Magically these tears crystallized into the Fairy Crosses.
Found along the Blue Ridge Mountains and occasionally in the northwest portion of North America, in Scotland, Brazil, Italy and France, true Staurolite crystals are uncommon. If the cross is perfect, the chances are that it was formed either from powdered Staurolite that was reshaped or from some other material. True Staurolite crosses are hard enough to scratch glass.
Fairy Crosses are said to bring good luck to the wearer. They also help ward off evil.