Iolite is the name for a gem-grade crystal of the mineral Cordierite. It is also called "water sapphire" because of it's brilliant color and transparency. Iolite has an odd optical property - it reflects light in a different color according to which direction the light is coming from. This property was used in ancient times to determine the direction of the sun in overcast weather. Viking mariners used thin chips of Iolite to determine the direction to shore when the sun was hidden by thick clouds and the shoreline was not visible in the distance. By seeing which color was reflected in the crystal, they could tell the direction of the sun. For this reason, Iolite is also called Viking's Compass.
The iolite crystals offered here have nice blue and purple coloration. They also have very good transparency and would be ideal for cabbing or faceting. This material comes from Brazil, but there are deposits in several localities around the world.
Refer to the photo. The black centimeter cube is shown for scale and is not included. You are purchasing one (1) iolite crystal selected from the larger lot shown. You will receive the largest piece remaining. Your purchase will include a labeled gemjar for safe storage,