The tourmaline group refers to a number of related species and varieties. The names commonly used in the gemstone business - names like Paraiba, rubellite and indicolite - are actually trade names, rather than gemological names.
The gemological names identify the different tourmaline varieties according to their chemical composition, not their color. This is the same convention used in the garnet group, where the term andradite, for example, is used to pick out the calcium iron silicates of the garnet family.
Most of the tourmaline that is sold as gemstones is elbaite, a lithium rich variety of tourmaline that occurs in transparent and translucent crystals in a wide range of colors. Elbaite is named after the Island of Elba in Italy, known as the site of Napoleon's exile after his forced abdication in 1814.
Another variety of tourmaline that is commonly found is schorl, an iron rich type of tourmaline that is opaque and black. Schorl is widely available - it accounts for more than 90% of the tourmaline in nature - and inexpensive. It is popular as a gemstone because it takes a good polish.
The less common tourmaline varieties include buergerite, dravite, liddicoatite and uvite. Buergerite, named after the MIT mineralogist Martin Buerger, is an iron-rich tourmaline variety that occurs in bronze, brown and black hues. Dravite is magnesium tourmaline that is dark-yellow to brownish-black in color. It is named after the Drava River area of what is now Slovenia.
Liddicoatite is a type of calcium tourmaline, named in honor of Richard Liddicoat, the GIA gemologist who invented the diamond grading system. It is found in a range of colors, including blue, brown, green, pink and red.
Uvite is magnesium/iron-rich tourmaline and was named after a province in Sri Lanka. It is usually dark-green to black in color. One of the unusual features of uvite is that it tends to form stubby crystals rather than long prismatic crystals like most other tourmaline varieties.
- First Published: July-16-2010
- Last Updated: October-07-2014
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