The name "iolite" originates from Greek and is a gemstone name given to stones of a blue color. It is a name created by combining "ion" (violet) and "lithos" (stone), and is sometimes called "ioliteco." It is called "cordierite" in mineralogy, named after the French geologist Louis Cordier, who first described iolite in 1813. Iolite is a transparent to translucent violet silicate mineral, characterized by pleochroism, appearing in two colors, yellow and gray, depending on the angle. When crystals are held up to the light and rotated, a mysterious phenomenon occurs where the blue becomes brighter or turns yellow. In ancient times, iolite was treated as a mysterious stone that reacted to some power, without understanding the cause of its strange phenomena. Beads: Approx. 9mm Inner diameter: Approx. 15cm Bundle discounts available.