Individuals born in October get to choose between two birthstones — tourmaline and opal. Each gem then unveils nearly limitless possibilities, as each one comes in a rainbow of shades and color combinations.
In fact, both of October’s birthstones came to earth through a journey involving rainbows, according to legend.
Between tourmaline (whose color depends on trace elements in its chemical makeup) and opal (which diffracts light to show a play of multiple colors), October’s birthstones offer a full spectrum of gems to suit anyone’s personal tastes.
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 gems 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:
- Schorl or black tourmaline 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 gem-quality. Schorl, in particular, is said to have protective powers against harmful radiation, toxins and anxiety.
- 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 it’s 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; but 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, but 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.
- 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.—mainly 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 jewelry.
One of this gem’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.
Ancient magicians used black tourmaline as a talisman to protect against negative energy and evil forces. Today, many still believe that it can shield against radiation, pollutants, toxins and negative thoughts.
Somewhere in Brazil in the 1500s, a Spanish conquistador washed the dirt from a green tourmaline crystal and confused the vibrant gem with emerald. His confusion lived on until scientists recognized tourmaline as a distinct mineral species in the 1800s. The confusion about the stone’s identity is even reflected in its name, which comes from toramalli, which means “mixed gems” in Sinhalese (a language of Sri Lanka). It’s a term Dutch merchants applied to the multicolored, water-worn pebbles that miners found in the gem gravels of Ceylon (now Sri Lanka).
It’s easy to understand why people so easily confuse tourmaline with other gems: Very few gems match tourmaline’s dazzling range of colors. From rich reds to pastel pinks and peach colors, intense emerald greens to vivid yellows and deep blues, the breadth of this gem’s color range is unrivalled. Brazilian discoveries in the 1980s and 1990s heightened tourmaline’s appeal by bringing intense new hues to the marketplace.
People have probably used tourmaline as a gem for centuries, but until the development of modern mineralogy, they identified it as some other stone (ruby, sapphire, emerald, and so forth) based on its coloring.
One of the earliest reports of tourmaline in California was in 1892. In the late 1800s, tourmaline became known as an American gem through the efforts of Tiffany gemologist George F. Kunz. He wrote about the tourmaline deposits of Maine and California, and praised the stones they produced.
In spite of its American roots, tourmaline’s biggest market at the time was in China. Much of the pink and red tourmaline from San Diego County in California was shipped to China because the Chinese Dowager Empress Tz’u Hsi was especially fond of the color. There, craftsmen carved the tourmaline into snuff bottles and other pieces to be set in jewelry. San Diego County’s famed tourmaline mines include the Tourmaline Queen, Tourmaline King, Stewart, Pala Chief, and Himalaya.
The miners became so dependent on Chinese trade that when the Chinese government collapsed in 1912, the US tourmaline trade also collapsed. The Himalaya mine stopped producing large volumes of gemstones. Other mines in San Diego County, like the Stewart Lithia mine at Pala, still produce sporadic supplies of gem-quality tourmaline.
The supply of tourmaline began to expand during the first half of the twentieth century, when Brazil yielded some large deposits. Then, beginning in the 1950s, additional finds appeared in countries around the world. Madagascar and Afghanistan have produced fine red tourmaline.