The name “tourmaline” is from the Singhalese (language spoken in Sri Lanka) “tura mali”, which roughly means “stone with mixed colors.” There couldn’t be a more appropriate name for this semi-precious stone, which comes in an endless variety of colors. With a 7 to 7.5 ranking on the Mohs Hardness Scale, they are durable, but not as strong as emeralds, sapphires, or of course, diamonds. Tourmalines are the birthstone for the month of October and a traditional gift for the 8th wedding anniversary.
The color of a tourmaline depends on the composition of its aluminum boron silicate structure. In addition to the fact that tourmalines can come in any color of the rainbow, some even change color depending on the lighting or have the color-changing effect of cat’s eyes. Traditional tourmaline variety names include Rubellite, the red or pink variety, Indicolite, the blue variety, and Chrome Tourmaline, an intense green from Tanzania. Because of the wide variety of tourmaline colors, it can sometimes be confused with other gemstones, for instance a green tourmaline with an emerald, which also derives its green color from trace amounts of chromium. Some tourmalines are bi or even tri-color. The different colors are sometimes zoned across the length of the crystal so that it may, for instance, have red on one end and green on the other. Alternatively, they may be zoned parallel to their length, so that a red crystal is surrounded by green, creating a watermelon tourmaline. These are sometimes sliced so as to highlight the full effect. Heat treatments and irradiation are used widely on tourmalines to enhance their colors, sometimes with very different results for the same colors from different locations. VMK does not sell heat treated tourmalines; each stone you get from us is a natural beauty! As a result, every tourmaline has a truly unique color. With such an endless variety of colors to choose from, the possible combinations for jewelry composed of a variety of colored tourmalines or fancy color diamonds and tourmalines are endless!
Many tourmaline crystals tend to be long and this guides the way that the cutter shapes the finished gemstone. Tourmalines are often fashioned into long rectangles, with cuts parallel to the length of the crystal. However, the gem cutter may also take into account tourmaline’s pleochroic properties, which cause it to absorb different amounts of light in different directions, and adjust the depth of the cuts accordingly.
As with other gemstones, tourmalines rise considerably in price once they reach larger sizes.
While as with most other gemstones, as the number of visible inclusions increases, the value of tourmaline drops, the degree to which an inclusion impacts the value depends on the hue and saturation of the stone. When stones have a vivid, attractive color, they can compensate better for inclusions, then others with light tone and low saturation. The most expensive types tend to be the blue indicolite, green verdelite and pink rubelite, with the most valuable being the rare neon-blue Paraiba Tourmaline, which was discovered in the Brazilian state of Paraiba in 1989 and has become extremely popular. Greens, oranges and browns are less valuable.
In addition to their use in jewelry, some large tourmaline specimens have been carved into wondrous sculptures, from abstract forms following the shape of the raw mineral, to animal and human forms. In 2013, Kaufmann de Suisse of Montreal created a necklace using the world’s biggest Paraiba tourmaline, a center stone weighing 191.87 carats. The Paraiba Star of the Ocean Jewels also features a 10 ct fancy yellow diamond.