Iolite History + Characteristics

Estate Natural Iolite Domed Cocktail Ring. Photo ©2019 EraGem Jewelry.   Iolite is a fairly new gem classified in the cordierite family. As such, it is a silicate mineral gemstone with magnesium, iron, and aluminum. Though cordierite has been around for a long time, iolite has only been known since the 1700s.  

Iolite History

Named in 1912, iolite actually held popular sway in jewelry before that. Throughout the 1700s, the blue crystal adorned jewelry in Europe. However, it seems to have fallen out of fashion for reasons unknown to me. In 1996, an American geologist by the name of W. Dan Hausal discovered the bluish-violet cordierite in Palmer Creek, Wyoming. Since then, Palmer Creek remains an important source for the stone. In fact, the largest known iolite crystal was discovered there in Grizzly Creek, Wyoming. This magnificent crystal weighs more than 24,000 carats. An astonishing find. Iolite elicited its name from the Greek word ios, which means "violet." Not surprisingly, it most commonly forms in hues of blue, ranging from pale to dark blue, often with a violet tinge. This beautiful gemstone also forms in shades of yellow, brown, gray, and green.  

Iolite Properties & Characteristics

Possibly the most interesting characteristic this bright blue stone displays is its pleochroism. Pleochroism refers to the way light reflects off the surface of the crystal. A pleochroic gemstone appears to be different colors when looked at from different angles. Sometimes referred to as dichroic, the gem may appear light blue from one angle and completely transparent from another. Some specimens even demonstrate three colors at different angles. Indeed, iolite demonstrates more visible color changes than most other pleochroic gemstones. As mentioned before, this special gemstone hails from Wyoming in the United States. Deposits also surfaced in Connecticut (USA), Australia, Canada, Norway, Myanmar, Sri Lanka, Tanzania, Madagascar, Namibia, and Brazil.  

The Compass Stone

The waters of the Arctic Sea are frigid. The cold temperatures combined with a sunny day often lead to what the locals refer to as sea smoke. Actually a misty vapor, sea smoke obscures the sun and other landmarks even on a clear day. In the time of the Vikings, when sailors navigated the Arctic Sea by sun and stars, this sea smoke created a problem. The Danish archaeologist Thorkild Ramskou first proposed that the Vikings solved this navigation issue with the use of iolite. By reading the Sagas and other Viking texts, Ramskou learned that the Vikings used a special "sunstone" to filter out the haze and locate the sun. He proposed that whatever this Compass Stone was, it had to be available locally, and quite abundantly. With its powerful pleochroism and its abundance in Viking territory, iolite fit the bill. Since Ramskou first proposed the notion, gem experts commonly refer to iolite as the Compass Stone. Of course, no one knows for sure which stone the Vikings used. However, modern navigational experiments have proven that iolite would work to locate the sun in sea smoke conditions in the Arctic. Therefore, it remains a strong contender.   ~ Angela Magnotti Andrews