The name "Iolite" is derived from the Greek word "Iol" meaning "Violet".

Depending on how the crystal has been cut it can take on different appearances; clear as water from one side, a honey yellow hue from another. The most popular cut gives it a rich blueish violet tone.

Iolite was used as a navigational tool by Viking explorers, who used thin pieces of the gem as a lens through which they could determine the exact position of the Sun, and thus safely navigate their way around the Earth.