Tourmaline, the beautiful semi-precious stone, is renowned for its extensive and exciting color spectrum. The chemical composition of this gem includes a group of closely related mineral species that share the same crystal structure. However, the presence of a complex mixture of other elements, such as calcium, manganese and iron, is primarily responsible for a tourmaline’s color.
This gem’s name is believed to have been derived from the Tamil and Sinhalese words "Turmali" or "Thoramalli" which translates to "stone with various colors". In addition to green, blue, yellow, pink, red, black and white (clear), a tourmaline is also found in bi-colors and tri-colors, with two or more shades in the same specimen.
Typically, it is the presence of iron and sometimes traces of titanium that result in blue and green tourmalines. Reds, pinks and yellows, on the other hand, are caused due to manganese.
It is believed that in the 1500s, a green tourmaline crystal was found somewhere in Brazil by a Spanish conquistador and was mistaken for an emerald. The tourmaline’s real identity, as a distinct mineral species, was confirmed by scientists only in the 1800s. New discoveries of this stone in Brazil during the 1980s and 1990s brought the spotlight on a tourmaline’s dazzling range of colors, which significantly elevated its appeal in the market.
Since tourmaline is a pegmatite mineral, it is extracted from pegmatite districts across the world, with Brazil still being the most significant source. San Diego County, including the famous Pala pegmatite district and Maine are also distributors of fine tourmalines. Malawi, in East Africa, mines striking yellow “canary” tourmalines, while blue-green tourmalines and fine rubellites can be found in Nigeria. Other sources of this gem include Afghanistan, Sri Lanka, Pakistan and Burma.
According to ancient folklore, it is believed that a tourmaline traveled over the rainbow and gathered its beautiful colors during the journey. Over the years, the properties of the tourmaline have been attached to different beliefs by different cultures.
In ancient India, tourmalines were used in various ceremonies to awaken insight and to help a person differentiate between good and bad. African civilization considered it to have the power to provide relief from disillusion and enhance mental clarity. Its pyroelectric property (ability to generate electricity when heated) made it popular among alchemists who linked it to the philosopher’s stone. This was said to be the substance that would give power over spiritual affairs, reconcile disputes, grant enlightenment and change base metals to gold. It is also believed to inspire creativity and was therefore used extensively as a talisman by artists and writers.
The glorious tourmaline is still used as an amulet by tribes in Africa, Native Americans, and aboriginal groups in Australia to protect them from all dangers.
Hardness & Strength
The tourmaline has a rating of 7 to 7.5 on Mohs scale of mineral hardness, which makes it fairly tough and a good option for jewelry, including rings for everyday wear. Tourmalines are also often used for other types of gemstone jewelry, such as earrings, necklaces and pendants.
In most cases, tourmaline gems available in the market are completely untreated. However, sometimes, they do undergo heat or irradiation to improve the color and clarity. This is especially true in the cases of red and pink tourmalines.
Typically, irradiation is used to intensify or develop the color. But the reaction of a tourmaline to this treatment depends on the original color and source of the stone. In general, yellow stones turn into an orange or peach color, while medium blue or green stones transform into a deep purple.
Tourmalines are usually heat treated to around 700° C to lighten the color. While both the treatments are stable sources of alteration, utmost care must be taken as this gem is prone to cracking when subjected to excessive heat. Changes resulting from heat treatment are stable and undetectable; however the effects of irradiation can fade when subjected to heat or bright light.
As a general rule, unenhanced and natural tourmalines are valued higher than the treated ones.
Quality & Grading
This fascinating gemstone occurs in a vast range of colors, from pink to black. While some commonly occurring tourmalines (like schorl) are fairly inexpensive, the rarer colors demand an exorbitant price. Here’s a look at some of the most popular tourmalines that have their own trade names:
Paraiba Tourmaline: Discovered in a gem pegmatite in the Brazilian state of Paraiba in 1989, this rare neon-blue stone is the most expensive of all tourmalines. The shortage in supply and high demand has significantly increased its value.
Rubellite: This variety of tourmaline is a popular alternative to ruby and red spinel, and can be found in large sizes. It is revered for its intense color, which ranges from hot pink to deep red and purplish-red.
Indicolite: This is a rarely occurring and one of the hardest tourmalines to be found. It displays colors that vary from gray-blue and vivid blue to blue-green.
Chrome Tourmaline: Another rare tourmaline, this particular type showcases a brilliant green color. The presence of chromium and vanadium are responsible for its splendid hue, which is similar to a tsavorite garnet. It was first discovered in Tanzania in the 1960s and is usually found only in small sizes and in very limited supply. A chrome tourmaline is, predictably, highly sought-after by collectors.
Watermelon Tourmaline: Multicolored gems are undoubtedly stunning, and this variety of tourmaline is one such gemological wonder. It typically displays a red center surrounded by a green outer layer (or vice versa). When used in jewelry, this particular tourmaline often showcases green on one side and red on the other.
Most colored tourmalines are formed in an environment that is abundant in liquids, hence during the crystal growth period, those liquids often get trapped inside as inclusions. Typically, the inclusions of a tourmaline resemble thread-like cavities or long hollow tubes.
Red and pink tourmalines generally have eye-visible inclusions, but those are often overlooked if the color is intense and attractive. However, tourmalines with prominent whitish inclusions, irrespective of the stone’s vibrancy, are considered undesirable by both dealers and consumers.
Green tourmalines, on the other hand, are usually eye-clean. The presence of visible inclusions, therefore, considerably lowers their value. The same applies for tourmalines in other colors; inclusions visible to the naked eye will significantly bring down the price.
A common characteristic seen in colored tourmalines is pleochroism, which means the color of the gem changes when viewed at different angles. In some cases, this effect is barely visible, while in others it is strongly apparent. Due to this property, it becomes crucial to cut the stone in a way that showcases the best color at most times. For this reason, light colored tourmalines are often carved into round, trillion and oval, while dark-hued tourmalines are emerald-shaped or elongated.
Green and pink tourmalines from certain localities have tiny, parallel inclusions. These stones, when polished and cut as cabochons, display a strong cat's eye effect and are called "cat’s eye tourmaline". Stones that are included, but have good color are also usually cut as cabochons to emphasize their hue and minimize the appearance of visible flaws.
This gem can be found in the form of fairly large transparent crystals that are used for producing exquisite tourmaline stones. Unlike sapphire and ruby, the price of a tourmaline doesn't increase dramatically per-carat. However, in the case of a fashioned tourmaline that showcases good color and clarity, the price per carat does go up as the gem passes the five-carat milestone.
Even though there is no standard quality grading parameter for tourmalines, the pink variety of this gemstone can be classified into the following categories based on the above-mentioned properties.
This category comprises of the top 1% of exceptionally rare pink tourmalines that range from slightly included to eye-clean. These beautiful gems can be distinguished from the others with their rich pink color.
Almost 10% of all natural pink tourmalines available belong to this category. These gemstones are slightly included and display a medium pink color.
This includes the top 33% of the available pink tourmalines. They are light to medium pink in color and have moderate inclusions.
Baby pink in color, this category includes the top 75% of available pink tourmalines that have heavy inclusions.
Tourmaline, when used in jewelry, looks elegant and striking. With proper care it can sparkle brilliantly for years to come. Here are a few tips that will help ensure the same:
Avoid subjecting your tourmaline jewelry to drastic temperature change as it can cause the stone to fracture.
Constant exposure to high heat can alter the color of the gem and must be avoided.
Use a soap solution and a soft bristle brush to clean your tourmaline jewelry. Ensure that you rinse well to avoid any residue.
Use a soft cloth to pat dry. Do not leave in the sun or use a hair-dryer.
Keep aside your tourmaline jewelry when engaging in outdoor activities like sports or gardening.
Tourmalines need to be wiped clean frequently as they tend to attract more dust compared to other gems.
Ultrasonic cleaners and steam cleaners are not recommended for this gem.
Store your tourmaline jewelry separately from other gemstones to avoid friction and scratches.
Consider storing your tourmaline jewelry wrapped in cloth or in a fabric lined box.
Tourmaline is not just stunning to look at; it is also reasonably tough and durable enough for all kinds of jewelry. Informed knowledge about the various physical and structural qualities of a tourmaline, as mentioned above, will help you choose a splendid piece of jewelry that you will cherish for a lifetime.