Indigo is a beautiful colour that sits between blue and violet and is often overlooked in designs, mainly due to a lack of gemstones that naturally exhibit this particular hue. However, there is one stunning gemstone that perfectly fits the brief – Iolite! Sometimes referred to as “Water Sapphire”, Iolite has been known and used for thousands of years.


Iolite (also known as Cordierite after the gemmologist Pierre Cordier) comes from the Greek word “ios”, meaning “violet”.  Typically, Iolite is more Indigo in colour, but you can also get specimens that are bluer and specimens that have a more violet hue.  When Tanzanite was first discovered in 1967, it was initially mistaken for being Iolite! Strongly pleochroic (colour changing) Iolite can display a blue to violet hue in one direction and pale yellow to colourless in another.


Because Iolite is fairly hard, it is often found in alluvial deposits (material deposited by rivers). In addition to the gem gravels of Sri Lanka, Iolite occurs in several areas of Africa, including Kenya and central Tanzania. Other iolite source countries include India, Brazil, and Norway. A significant new Iolite deposit was discovered in Madagascar in 1994. 


Only officially named in 1912, Iolite has been used and admired for centuries. According to legend, Iolite is called the “Viking Compass Stone”. It’s said that thin slices of iolite served as glare-reducers and polarising filters that helped ancient Viking navigators locate the sun on cloudy days. This allowed the Nordic mariners to pinpoint their own location on the seas! Iolite was very popular in the 18th Century in Europe but today it is used somewhat infrequently and has yet to catch on with retailers as dramatically as Tanzanite did in the 1970s and 1980s.


Nowadays, Cordierite, the mineral which Iolite comes from, also has industrial uses. It is used as an electrical insulator and in heating implements. Iolite is also used to commemorate the 21st wedding anniversary and overall is an abundant and reasonably priced gemstone to be used in jewellery-making. 


This silicate of Aluminium, Iron, and Magnesium has two distinctive features - a beautiful, violet-blue hue derived from Iron and a striking, eye-visible pleochroism. Iolite falls between 7 and 7.5 on the Mohs hardness scale but given that it has distinct cleavage in one direction, its toughness is only fair. This makes Iolite vulnerable to breakage when set in a ring or other setting exposed to rough daily wear. Unlike Tanzanite, Iolite is rarely heat treated.


Legend describes Iolite as a way to strengthen one's eyesight. There are also said to be many emotional attributes to the stone such as the ability to enhance one’s curiosity and achievement whilst guiding one through spiritual growth. It is also thought to enable oneself to overcome co-dependency with a partner and bring friendliness and higher, purer thoughts.