Iolite is a transparent gemstone variety of the mineral cordierite. Iolite varies in color from sapphire blue to blue violet to yellowish gray to light blue as the light angle changes. A cube cut from iolite will look a more or less violet blue, almost like sapphire, from one side, clear as water from the other, and a honey yellow from on top. The name "iolite" comes from the Greek ION, which means violet.
The legends say that when Leif Eriksson and the other legendary Viking explorers ventured far out into the Atlantic Ocean, away from any coastline that could help them determine their position, they had a secret gem weapon: iolite. The Viking mariners used thin pieces of it as the world's first polarizing filter. Looking through an iolite lens, they were able to determine the exact position of the sun, and navigate their way safely to the New World and back.
The property that made iolite so valuable to the Vikings is its extreme pleochroism and the old name for iolite is "dichroite", a Greek word meaning "two-colored rock". It has also been called "Water Sapphire" and "Vikings' Compass". Iolite is surprisingly affordable, the richer the blue, the better. Iolite is sometimes used as an inexpensive substitute for sapphire but it is much softer and should be protected from blows.
Nevertheless, iolite is relatively hard and with its attractive color and reasonable price is used in all types of jewelry. Iolite is cut into gemstone facets and cabochons and used to make rings, earrings, and pendants. The Vikings probably mined their gems from deposits in Norway and Greenland. Iolite is also found in India, Sri Lanka, Burma, Mozambique, Zimbabwe, Madagascar, Namibia, Tanzania, Australia, Brazil, Canada, and the United States. The largest iolite crystal found weighed more than 24,000 carats, and was discovered in Wyoming, USA.
