Buy or sell iolite gemstones. Iolite is a transparent stone which displays different colours in different directions in the crystal. A cube cut from iolite will look violet blue, almost like sapphire, from one side, clear as water from the other, and honey-yellow from the top. This property, called pleochroism, makes cutting iolites difficult. When cut properly, iolite is usually a purplish blue with an attractive softness.