Iolite is a violet colored gemstone. It's name is derived from the greek ios (violet) and lithos (stone).
It was sometimes called the "water sapphire" because of it's color.
In France and England during the 18th century, rings, necklaces and broaches were often set with gems the first letters of which, combined, formed a sentiment. (FAITH)
Fire-opal, Alexandrite, Iolite, Tourmaline, Hyacinth.
When this gemstone is worn it is said to renew faith.