TOURMALINE

TOURMALINE	October's birthstone
Major Sources	Afghanistan, Brazil, Kenya, Madagascar, Mozambique, Nigeria, Sri Lanka, Tanzania, Zambia & USA
Colors Found	Various
Family	Tourmaline
Hardness	7 to 7.5
Refractive Index	1.61–1.66; Uniaxial (–)
Specific Gravity	2.82–3.32
Crystal System	Trigonal
Enhancements	May be enhanced

Boasting a colorful and romantic history, tourmaline rivals all but the most unique gems as it is found in an incredible array of gorgeous colors. Coming in a palette of over 100 different hues, tourmaline is one of the world’s most diverse gemstones. This has resulted in the nickname “the chameleon gem,” which is doubly appropriate when you consider that one major source of tourmaline is Madagascar, home to more than half of the world’s chameleon species.

The name tourmaline comes from the Sinhalese word turmali, meaning mixed, due to a historical tendency for it to be confused and then mixed with other gem varieties.

Legends and lore

Sri Lanka (formerly Ceylon) was also partly responsible for tourmaline’s reappearance in Europe when tourmaline gems were sold to Dutch traders who imported them to the west in the 15th century.

The Dutch, aside from admiring tourmaline for its beauty, first discovered that this gem, like quartz, possessed a unique property, piezoelectricity.

Tourmaline when heated or rubbed creates an electrical charge, becoming a magnet that attracts lightweight materials.

A monarch particularly enchanted by tourmaline was the Empress Dowager Tz’u Hsi, the last Empress of China. She loved tourmaline so much, and was so wealthy, that she bought almost a ton of it from San Diego, California’s pegmatite district.

Just the facts

While tourmalines occur in large crystal sizes, tourmaline of sufficient beauty to be set into jewelry is not available in great abundance. Because of their size, crystals are sometimes cut into long rectangular shapes following the axis of the crystal.

Tourmaline crystals occur in granitic pegmatite veins occurring in the great gem mining districts of Minas Gerais in Brazil, San Diego County in the USA, and the East African countries of Kenya, Tanzania, Mozambique, Malawi and Madagascar and Nigeria.

Tourmaline is a group of mineral species. However, it’s the mineral elbaite (named after the island of Elba near Italy’s west coast where it was discovered) that is responsible for almost all of tourmaline’s most famous gem varieties. When used, the name elbaite typically references green tourmaline, while the other colors of elbaite have their own specific color-related names.

A bright yellow tourmaline from Zambia’s Lundazi area is termed canary tourmaline. Tourmaline very occasionally displays the cat’s eye effect. Chatoyancy or the cat’s eye effect is a reflection effect that appears as a single bright band of light across the surface of a gemstone.

All tourmalines can display pleochroism, meaning that its color changes when viewed at different angles. However, this can vary from specimen to specimen. In some, this effect is hardly noticeable, while in others it is strongly apparent. To bring out the best color, gemstone cutters must take this into account when faceting tourmaline.

Green tourmaline

Typically free from inclusions, green tourmaline offers gem consumers everything they want in an emerald, but with more clarity. Green tourmaline has become popular with collectors over recent years as they realize the true potential of this beautiful gem. Chrome tourmaline is an intense green variety of tourmaline found in East Africa. Despite the name, most chrome tourmaline is actually colored by vanadium.

Indicolite tourmaline

Ranging in color from bright to deep blue, indicolite tourmaline is rare and high quality specimens are highly collectible. Indicolite is strongly pleochroic (showing different hues when viewed from different directions). As indicolite appears darker when viewed down the c-axis, this must be taken into consideration when cutting, as a loss of transparency and brilliance can occur in darker specimens. The Romans reportedly used indicolite, particularly in carved brooches that often bore the images of animals, as they believed it possessed strange occult powers. It was rediscovered in Europe in 1703 when the Dutch imported indicolite they had obtained in Sri Lanka. Generally, only indicolite less than one carat is available and as a result, bigger sizes are very rare and prized as special members of the tourmaline family.

Bi-color tourmaline

Mentioned in early 20th century gemological texts, it was not until the 1970’s that bi-color tourmaline lent its charm to jewelry. Treasured for the magnificent harmony of its two colors, bi-color tourmaline possesses a distinctive beauty created by chance.

Due to its complex chemical composition, tourmaline comes in many colors. Bi-colored tourmaline occurs because of differences caused by environmental changes. At different times, various color-causing elements (iron, manganese, titanium, chromium and vanadium) were incorporated into the crystal, causing different color layers. Purposefully cut to showcase this feature, bi-colored tourmaline displays a gorgeous contrast between its colors, typically pink and green, in one gem.

Given the environmental changes endured by bi-color tourmaline, like many tourmalines (paraíba or rubellite), inclusions are common. Far from being flaws, inclusions are a hallmark of authenticity that record a gem’s natural relationship with the earth.

Bi-color tourmaline should not be confused with watermelon tourmaline. Watermelon tourmaline is a crystal with the inner part showing pink surrounded by green. They are typically thinly sliced in sections, like a loaf of bread and polished to show the “watermelon” effect.

Paraíba tourmaline

The world was introduced to paraíba tourmaline by Brazilian miner Heitor Dimas Barbosa in 1989. Convinced there were fine stones in the hills of the Brazilian state of Paraíba, he took five years before unearthing his first paraíba tourmaline crystal.

While paraíba tourmalines were first found in Brazil’s Paraíba State, stones of similar color and composition have now been found in the neighboring Rio Grande do Norte State (Brazil). The first African find was discovered in 2001 at the Edoukou Mine in Oyo (Nigeria), close to the border of Benin. Also in 2001, yucca root farmers in Mozambique’s Nampula Province discovered paraíba tourmalines. This material did not hit the market in a big way until 2006.

When paraíba tourmaline was first discovered in Brazil, the unusually intense “neon” or “electric” colors set it apart from any other tourmaline previously known. The color of this gem ranges from intense emerald green through Windex blue to a rich sapphire blue and continuing along the spectrum to indigo, intense violet (similar to fine amethyst), purple and even red. Apart from the intense colors, a key feature of these gems is their relative lack of extinction.

Paraíba tourmaline is extremely brilliant, glowing even in low light; it displays electric Windex blues, neon peacocks, sizzling turquoises or dazzling twilight blues. While personal preferences play a part, traditionally the Windex blues are the most coveted. Top Brazilian paraíbas can fetch as much as $30,000/ct or more in the wholesale gem market. Fine African gems can also be worth thousands of dollars per carat, making the African stone a tremendous value.

Paraíba tourmaline owes its spectacular colors to small amounts of copper, with manganese and iron. Higher quantities of copper produce more blue and turquoise colors, while elevated manganese gives more violet and red hues. Iron is thought to be a factor coloring the greens.

Does every tourmaline that contains a certain amount of copper/manganese/iron qualify as a paraíba-type? In a word, no. The most important feature of a paraíba tourmaline is exactly that which made the gem famous in the first place—intensity of color. Gems that lack the requisite color intensity or those with too much extinction should not be sold as paraíba. GemsTV markets those lighter colors under the names Mozambique tourmaline.

Paraíba tourmaline is typically a richly-colored gem that displays electric windex blues, neon peacocks and sizzling turquoises. Initially discovered at Mina da Bathalha, Paraíba, Brazil, it possesses an intense color that allows the gem to glow and shine even when there is little light.

While most paraíba tourmaline is under one carat, gems from Mozambique comes in sizes of up to 40 carats or more. Like emeralds, inclusions are common in paraíba tourmaline, making its color the main beauty determinant. However, when paraíba tourmaline is clean, its rarity and value increase exceptionally. Its beautiful vivid colors have made paraíba tourmaline hugely popular within a short time. One of the world’s most desired gemstones, paraíba tourmaline is a gem whose impossible rarity is only surpassed by its unrivaled beauty.

Rubellite tourmaline

Rubellite’s sensuous mélange is the personification of seduction; no other colors display its comparable flair. Whispering in passionate pinks and suggestive purples, rubellite affords the perfect romance in an opulence of red. Rubellite, deriving its name from the Latin word rubellus, meaning “coming from red” is a lustrous, reddish pink and purple-toned variety of tourmaline. In the 17th century, the Tsar of Russia commissioned many items of gemstone jewelry to be made for the Imperial Crown Court. However, gems that were originally thought to be rubies, have later been discovered to be rubellite.

Extremely rare, rubellite has taken the jewelry world by storm in recent years following the discovery of new deposits. Madagascan rubellite heralds from mines located 26 miles from the town of Betafo, in the Antananarivo province in Madagascar’s central highlands. Interestingly, this deposit produces some truly unique rubellites whose color is close to that of famous rubies.

Major rubellite finds date from the 19th century, when they were discovered in Brazil. This country continues to be a major supplier, particularly in Minas Gerais state. Some of the finest stones came from Ouro Fino, in Coronel, Murta (Minas Gerais). Discovered about 1983, by 1985 the deposit was already exhausted. Ouro Fino rubellite acquired legendary status in the gem world.

Surprisingly enough, Southern California’s Pala District was also once an important source, particularly in the late 19th and early 20th centuries. The blue-capped rubellite crystals from the Tourmaline Queen mine are world famous among mineral collectors.

In the summer of 1998 a new tourmaline deposit was discovered in a farming area 25 miles from the ancient city of Ibadan in Nigeria, West Africa. This material was exceptionally clean and well saturated. Within just a few short years, over 1000 kg of rough was taken out of the ground; and just as quickly as it appeared, it was gone.

In 2007, another major find was made, this time near Chimoio, Mozambique (near the border with Zimbabwe), with colors similar to Nigeria.

With the exception of ruby and red spinel, rubellite is the only other gemstone that occurs in such a rich, dark red color. Similar to emerald, inclusions in rubellite are common. The chemical element that colors rubellite (manganese) actually causes a growing crystal to become internally flawed (i.e., the more manganese present, the darker the red color, and the more imperfect the final crystal). It is therefore extremely rare to find a richly colored rubellite that is internally clean. Rubellites also tend to have more natural inclusions because they are formed near the center of the crystal pocket, and thus receive more stress and pressure during their formation. Regardless, rubellite is a durable gemstone, well-suited to everyday jewelry.