:(Fe, Mg, Zn)2
(OH) (Hydrous iron magnesium aluminum silicate)
Staurolite is a relatively cheap gem with some interesting properties. Usually colored a dark red or brown, staurolite crystalizes into hexagonal prisms. These prisms grow upwards, similarly to columns. Often, staurolite is found twinned, meaning that crystals grow into each other to form one crystal with different branches. Staurolite's twinning occurs uniquely, as there are only two different types of twins. The first type is similar to St. Andrew's Cross or an X, two crystals grow together with a 60° angle between them. The other version of twin is a 90° cross, similar to a plus sign, +, or the Christian cross. Because of this, these 90° twins are often worn as pendants on necklaces by Christians. Even the name comes from the Greek, stauros lithos, meaning cross stone.
Staurolite was believed to be created by the tears of fairies whom could not help but cry when they heard of Christ's crucifixion While this is obviously an old Christian myth, it has stuck with the stone. Staurolite is often called "fairy stone" or "fairy cross". Since the first time it was worn, it has been considered a good luck charm as well as a charm that would protect children from evil spirits.
Staurolite does not seem to have many uses outside of cross-shaped pendants and looking pretty in a collector's collection. It lacks both the lustre and translucency of a precious gem. However, it does have one important use to geologists. Staurolite is only formed metamorphicly and can be found in matrices of gneiss and schist. Because it's only formed in that particular manner, it can be useful to identify/narrow down a type of unknown stone.
Clutches of staurolite have been found in Taos, Russia, New Mexico and Georgia. In 1976, staurolite was named the state mineral of Georgia. According to one internet source, staurolite crosses are often faked, so be sure to take care when ordering staurolite online, if so inclined. Run some tests at home when you receive the stone, it should be able to scratch glass and not be scratched by a knife.
Precious Stones, by Dr. Max Bauer. Charles E. Tuttle Company: Rutland Vermont and Tokyo, Japan, 1969
Gemstones of the World, by Walter Schumann. Sterling Publishing Co., New York, 1979
Simon and Schuster's guide to Rocks and Minerals, Simon and Schuster Inc. New York, 1978