Iolite gets it's name from the Greek words 'ios' meaning violet and 'lithos' meaning stone. 

A unique feature of iolite is that a cube cut from an iolite crystal will look clear as water from one side, display a violet blue color not unlike a sapphire from another side, and look a honey yellow color from the top.   This property is called extreme pleochoism.  In fact, some people early on referred to the gem as 'water sapphire', a name now obsolete.

The ancient Vikings of Leif Eriksson knew about this unique property of iolite and they used thin pieces of iolite as the world's first polarizing filter.  When they looked through an iolite lens, they were able to determine the exact position of the sun.  This enabled them to navigate safely and venture far out into the Atlantic Ocean.  Because of iolite, they were able to sail to the new world and back.

Iolite is mined in India, Sri Lanka, Mozambique, Zimbabwe, and Brazil. Very affordable now, iolite is expected by many experts to become a jewelry staple in the future