The name “tourmaline” comes from the Sinhalese words tura mali, which mean “stone of mixed colors.” As its name implies, tourmaline stands apart from other gemstones with its broad spectrum of colors in every shade of the rainbow.
Tourmaline is not one mineral, but a fairly complex group of minerals with different chemical compositions and physical properties. Certain trace elements produce distinct colors, and many resulting varieties have their own names.
Black tourmaline, known as “schorl” is rich in iron, which causes dark shades from deep brown to bluish-black. This variety makes up 95 percent of all tourmaline, though most of it isn’t gemstone-quality.
Dravite or brown tourmaline is rich in magnesium, which causes colors ranging from brown to yellow. It’s named for the Drave District of Carinthina (now Slovenia) where this stone is found.
Elbaite offers the widest range of gem-quality tourmaline colors, due to lithium traces combined with other coloring elements.
Rubellite or red tourmaline is caused by manganese. However, if the color becomes less vibrant under different light sources, it may be called pink tourmaline.
Indicolite or blue tourmaline can appear purplish blue or bluish green, depending on the amount of iron and titanium.
Verdelite or green tourmaline can resemble emerald. However, if its color is caused by chrome and vanadium, it’s called a chrome tourmaline.
Paraíba tourmaline is a vividly colored purplish or greenish blue variety found in Paraíba, Brazil. It’s the most recently discovered, and because of its desirably intense colors, it’s one of the most valuable. The element copper is responsible for its vivid colors. Copper-bearing tourmaline is also found in other parts of the world such as Mozambique and Nigeria; but only copper-bearing tourmaline from Paraíba, Brazil is called “Paraíba tourmaline.”
Achroite or colorless tourmaline is rare.
Parti-colored tourmaline displays more than one color, due to chemical fluctuations during crystallization. A common color combination is green and pink. These are often cut in slices to reveal a red center surrounded by a green rim, earning the name “watermelon tourmaline.”
Tourmaline is mined in Brazil, Sri Lanka, Nigeria, Mozambique, Madagascar, Afghanistan, Pakistan and the U.S.—primarily Maine and California.
Tourmaline is desirable because of its sheer range of color options. Combined with a good hardness of 7 to 7.5 on the Mohs scale, tourmaline makes very wearable birthstone jewelry.
One of this gemstone’s most impressive traits is its ability to become electrically charged through heat (pyroelectricity) and through pressure (piezoelectricity). When charged, tourmaline can act as a magnet by oscillating and by attracting or repelling particles of dust.