by Debjani Banerjee
The recent trend in the jewelry line is to label each tourmaline by its color as opposed to its original name.
Tourmaline is a gemstone occurring in many colors, the crystalline stones come in more than a hundred hues! Scientifically it is a group is a group of minerals related in physical and chemical properties. The origin of the word comes from Sinhalese “turmali” meaning mixed. It is possible to replicate almost any gem with a tourmaline, unless one can actually differentiate it! The mineral elbaite is the most prominent of all its constituents, responsible for all the gem varieties; the others are dravite, schorl, liddicoatite, veredite, tsilaisite, etc. The recent trend in the jewelry line is to label each tourmaline by its color as opposed to its original name. The current gem trade names doing the rounds are as follows.
- Anchorite- a colorless variety of tourmaline.
- Bicolor- these are unique; no other gemstone resembles them except the lovely Ametrine, which is a mix of purple amethyst and yellow citrine.
- Cat’s eye- these come in pink and green colors. In some tourmaline crystals inclusions of other minerals occur, these tiny parallel inclusions cause a lovely cats eye effect when polished. These are cut as cabochons.
- Chrome- this rare tourmaline comes in rich green colors, chromium vanadium oxide is the element in these stones, which also causes the green in emeralds. Some of these tourmalines have the color of a top grade emerald and are more durable! These come from Kenya, Zambia, Namibia, and Tanzania.
- Dravite is normally brown; these are often heat treated artificially to lighten color.
- Schorl- dark grey to black, these stones have no gem value, and are used in the crystal form, often as mourning jewelry.
- Elbaite is the most recognized of the tourmaline colors. These are eye clear stones, cut in rectangular shapes. These range from pastel greens to vibrant greens.
- Indicolite- range from the finest blue to medium dark blue, closely replicating sapphire, these come from Srilanka, Brazil, Madagascar, California, and Maine. These are typically clear gems, with rare inclusions visible to the eye, very valuable, because of its beauty.
- Orange yellow- this variety has no commercial name but is available in all the shades in between. These lovely stones are a popular choice.
- Paraiba- Earlier known as neon and electric tourmaline, this was discovered in 1789 in Paraiba in Brazil. These are very vivid blue greens and have copper and gold in its composition. These are very rare and expensive and mined from deep hand hewn mineshafts, naturally the supply is limited, and these are collector’s gems.
- Pink tourmalines- are favorites for mounting on rings and pendants; these vary from light pinks to hot pinks, to violet shades in between. The light pinks are cobalt treated to turn a fiery hot pink!
- Rubellite- the deepest shades of this stone appear ruby red, the Russian crown jewels had a lot of rubies, which were later found to be rubellites! These are clear stones with inclusions in the center of the crystal, which give it the rich red color; red rubellite is the most expensive tourmaline. A super clean stone is probably a radiated or heat-treated pink tourmaline.
- Watermelon or tricolor tourmalines are green and red with a white separation, heavy in inclusions, clean gems. These are expensive and are considered a collectors gemstone.
Every color of tourmaline can be found in Brazil. Pink, green, purple are mined in Tanzania, Kenya, Madagascar, Afghanistan, and Srilanka. Maine has lovely sherbet colors; California has perfect pinks from its famous Himalaya mine, once the favorite of a Chinese empress who had huge quantitities ordered. Tourmaline crystals are long narrow pencil thin crystals cut in long rectangular shapes. Tourmalines are usually cracked and flawed, especially in the pink, red, bicolor varieties, the blues, greens are usually clean and costs can be very high for stones above 10 carats.
Tourmalines can be recognized from other stones by two distinct properties pyroelectricity, when heated and cooled, the stone attracts dust particles. Because of its atomic composition, an electrical charge is generated which causes it to attract light particles. The other is plechroism, the color of the stone changes when held at different angles in varying light. Dark stones can be made lighter with heat-treatment, light pink stones darker with cobalt irradiation technique. Tourmaline is a good choice for jewelry, yet the expensive stones have to be treated with care, rough treatment can scratch the gems, a light rub in warm soapy water is the best care you can take of your new acquisition.