Iolite is a variety of the mineral cordierite. This mineral was named after French geologist Cordier. The name iolite comes from ios, the Greek word for violet. Iolite is commonly known as "water sapphire" in its deep blue sapphire color.From one direction, iolite can appear sapphire-like blue and from another, it can appear as clear as water. Furthermore, from the top view down, it can appear light golden or honey-yellow in color. 'Dichroite' is another synonym for iolite in reference to its pleochroic ability; 'dichroite' is a Greek word which loosely translates as 'two-colored rock'.