Tourmaline: The Electric Stone

It took nearly three hundred years for gemologists to recognize tourmaline as a unique gemstone.  Although considered a semi-precious stone, tourmaline is found in a wide range of beautiful colors that can rival some of the world’s finest gems.  From peachy pinks to forest greens, there is truly a tourmaline for every taste.  Read on to learn more about this fascinating gem.

Tourmaline History

The name tourmaline umbrellas a group of minerals with similar crystal structures, but varying chemical compositions.  It was first discovered in Brazil in 1554, although it was believed to be emerald at the time.  It wasn’t until the 1800’s that tourmaline was recognized as its own mineral.  In addition to being green, tourmaline is also found in the colors red (also known as rubellite), pink, orange, yellow, blue, brown (dravite), and black.  Adding to the confusion in identifying tourmaline, is its strong pleochroism (displaying different colors depending on the angle it is viewed from).  In fact, the name comes from the Sinhalese word “toramalli,” meaning “mixed gems”.

It was the gemologist George F. Kunz who, while working for Tiffany & Co,  promoted the use of tourmaline in jewelry after deposits of the gem were found in Maine and California in the late 1800’s.  In addition to America and Brazil, tourmaline is also found in Sri Lanka, Afghanistan, Australia, and all over the continent of Africa.

Special Tourmaline

Tourmaline can be found displaying a chatoyancy, also know as cat’s eye.  Due to the crystal structure of the gem, this cat’s eye effect isn’t as sharp and dramatic as the more popular cat’s eye chrysoberyl.

Perhaps the most recognizable specialty variety is the watermelon tourmaline, which is cut to display the pink-red color transitioning to green, with a white band in between.  Maine is famous for its watermelon tourmaline, and although not the sole producer, boasts some of the finest specimens.  In fact, tourmaline is the official state mineral of Maine.

A unique characteristic of tourmaline is its ability to produce and hold an electric charge when heated, or physically stressed or squeezed.  These characteristics are referred to as pyroelectric and piezoelectric, respectively.  This is why tourmaline is also known as “the electric stone.”

Tourmaline in Jewelry

With a Mohs Hardness of 7 to 7.5, tourmaline is harder than other semi-precious gemstones.  This, along with the wide range of beautiful colors it comes in, makes tourmaline a great choice for setting into jewelry.  Due to its crystal structure, you will often find the gem cut into long baguette and marquise shapes, creating an elegant look.  Some believe that wearing tourmaline can invite positive energy and protect from negativity.  Along with opal, tourmaline is an October birthstone, as well as the stone associated with the eighth wedding anniversary.

Shop Market Square Jewelers' current tourmaline collection here.