Tourmaline Facts and Buying Guide
by Shweta Dhanuka
It is the hard stone having the hardness of 7-7.5 Mohs and could be used for wearing daily in earrings, rings or pendants. However, in order to endure years of wear keep it away from steam cleaning, home ultrasonic cleaner and heating. It should also be protected from scratches and sharp blows.
Tourmaline, the name is derived from the Sinhalese word “tura mali,” that was referred as mixed assortment of colored gemstones. The name of this semi precious gemstone is justified with its source name as it is found in many different colours and in diverse colour combinations. This is the reason why it is very close to the heart of people with the creative and artistic instinct.
It is the gemstone for the August born person and wedding anniversary stone for the couples in the 8th year of their marriage. Being a versatile gem, no two gemstones are similar in appearance. The difference lies in colour and facets of the stones. Therefore, while making the purchase of this splendid gemstone, give time to see it under different light source. Specific light sources are suitable for different colours. Read this and more about the varied varieties along with common characteristics of Tourmaline in the text below. It is written to make the buyers fully acquaint with the diverse facts about the gemstone that would act as buying guide. This would enable the buyers to make the purchase of actual gemstone at the right price.
Colour -This gemstone occurs in all possible hues, tones and shades of colours. The multiplicity of colour for this gem is not restricted to the rainbow colours rather it is found in almost all the primary and basic colours like shades of green, red, blue, yellow, brown, pink, black, colourless etc. The colour disparities along the gemstone’s length lead to the bicolour and tricolour crystals that have whole host of colour amalgamation. In simple words, bicolour tourmalines are those that display two colours while tricolour display more than two colours in the same stone. These varieties having colourful bands are quite fashionable. Combinations of different colours in concentric circles and triangular patterns in one single stone are also commonly seen like one colour at the center of the stone while other colour around it.
This entrancing stone exhibits strongly the phenomena of Pleochroism. Under it, the crystal is seen in diverse colours is diverse directions. There is mix of dark, medium and light shades of the colour. Different colour shades are seen along the vertical and horizontal axis. The maximum dark colour shade is at all times observed from the bottom axis of the crystal.
Varieties – On the basis of the colour this gemstone is classified into ten varieties. Colour variations occur due to presence of different mineral in the chemical composition in form of impurities. All the different types are exclusive and special for the jewelry lovers. Sometimes the jewelry designers create incomparable ornaments using all the colour varieties in form of rainbow.
Watermelon Tourmaline – This is only one of its kind variety having pink colour in the heart of the stone and green colour encircling pink. It is the best example for colour variation in cross-section that appears in concentric circles. Jewelry designers create fabulous ornaments using it in a very unique way by setting it in slices instead of faceted stones so as to boaster the incredible phenomenon.
Paraiba Tourmalines – It is a stone blue to bluish green in colour. Minute quantity of copper and a tad of gold are responsible for the colour. In the year 1987, it was first mined in Paraiba State of Brazil and so named accordingly. This variety is to a large extent in demand when found in good quality. Gemstone lovers procure it as the lifetime asset.
Red Tourmalines – It is also called as Rubellite. Mineral responsible for red shades is lithium. The colour of the stone varies from pale rose to deep ruby red with the minimum to maximum quantity of lithium present in the composition respectively. Absolute deep ruby red shade is very rare to be seen thus is very expensive. Finest quality is acquired from Nigeria. A genuine high quality red colour stones shows same intense red colour in incandescent light plus in daylight. Poor quality stones would display brown hues in change of light source. It is believed to have prominent sway on love and friendship, leading to permanence and firmness in everlasting relations.
Blue Tourmalines – Across the world this variety is in high demand but because of the limited supply it is not easily obtained. Nigeria is the prime source for the best quality gems. Indicolite and Indigolite are additional names for this variety. The originality of this colour could be judged in daylight. It is alleged to radiate high grade of concord and the wearer is trusted to experience frankness and patience. It could be seen in different shades blue, black and brown in triangular pattern.
Yellow Tourmalines – It was first found in the mines of East Africa. The gemstones acquired from Malawi in Africa possess brilliant clarity thus are named as ‘Canary’. The pure yellow colour without the traces of any other colour appears due to the fine quantity of magnesium in the composition. Alas, every single stone is not intense and clear yellow in colour. Therefore, the pale stones are treated with circa at 700 degree Celsius to achieve the desired bright colour. Difference between original and enhanced stone could be distinguished in incandescent light.
One matchless aspect of this colour variety is that it can be distinguished with its excellent fragrance. Malawi canary or yellow tourmalines as rough are covered with black coating when it is obtained from the mines. The first step of processing for this variety is to separate the stone from the unwanted black material. So the roughs are boiled in the mixture of water and lemon juice. As a result the black material is removed and the stones exhibit dazzling lemon yellow colour with fantastic aroma.
Green Tourmaline – It is gaining popularity at the rapid pace. Fortunately with good supply it is sort of affordable. As pink gem suits females, green is for males as it endorses male stability and safety. It is also called as Verdelite or Elbaite. Green colour is due to the presence of chromium mineral in the composition. This stone is best observed in daylight.
Black Tourmalines : It is the iron-rich variety hence is black to bluish-black to deep brown in colour. It is said to defend the wearer against pessimism. Schorl is it’s additional name. Commonly used for engravings and in esotericism as it is believed to protect its wearer against detrimental waves.
Pink Tourmaline – It is available widely thus is reasonably priced. It is more apposite for females as it encourages female balance and security.
Colourless Tourmaline : As the name specifies it is having no colour. It is called as Achroite and is rare in nature.
Brown Tourmaline – It is further more rare than the colorless variety. It is also called as Buergerite and Dravite. These varieties are not very popular.
Clarity – This fabulous gemstone is found in large crystals as rough. Absolutely crystal clear gems are rarely obtained. The majority inclusions in tourmaline are fractures and liquid-filled healed fractures. In some stones needle like inclusions are also seen. However, clarity varies from one stone to other with respect to its colour. For example – Blue and green coloured gems consists less inclusions than red and pink stones. Moreover, the commonly occurring inclusions could be removed with efficient cutting. Minute fine and soft inclusions are sometimes appreciated and do not affect the price.
Cut – It can be cut into any shape and size. However, it is not that simple for the cutter. For this multi-colored gemstone cutters need to use his/her skills at the optimum level to identify the right angle and side of cutting so as to maximize the effect of Pleochroism. In order to enhance the main colour, it is suggested to check the colour spots from all the directions before cutting. The final look of the gemstone is totally in the hands of cutter.
Dark colored gems are cut in a way that exhibits two lighter pleochroic colours. Such stones have c-axis cut in parallel to the outer facet. Similarly, light colored stones are cut to highlight the pleochroic deeper shades. To achieve this, light shades are cut having c-axis perpendicular to the outer facet. The phenomenon of Pleochroism is best seen in long rectangular shapes. Also due to long and narrow crystal shapes of the gemstone, rectangular cut is best to view the real beauty of the gem. Some stones displaying cats-eye effect are cut into a cabochon as in this cut the upshot is boosted. Emerald and oval cuts are next in the list of preference. Rounds, triangles and trillions cut are followed then after.
Carat weight – Different varieties are found in different carat weight. Paraiba gems are found maximum to 2 carat weight. More than this weight, the crystals are considered as gems only for royal families. Red, blue and green gems could be found between 3-5 ctw and beyond 10 ctw is rare and too costly. Yellow gems could be procured between 1-3 ctw. Rest others tend to be less than 3 ctw.
Price – This stunning gemstone could be an affordable gem as well as an expensive buy too. It all depends on the colour varieties and their respective quality and supply. Paraiba tourmalines are the priced maximum then follows blue, green, red and watermelon gems. Intensity, rarity and clarity of these varieties further affect the price. Final price is ascertained on the basis of the carat weight. With every increase in the carat weight of the gemstone the equivalent price increases.
Occurrence – This gemstone is amongst the most complicated silicate mineral. Being a complex silicate of Aluminum and Boron, its chemical composition varies with the presence of varied minerals like sodium, calcium, iron, magnesium, lithium and many more. Granite & granite pegmatite igneous rocks and marble, sandstone & schist metamorphic rocks are the rocks where tourmaline occurs. Lithium-rich stones and Magnesium-rich stones occur in igneous and metamorphic rocks respectively. It has the Trigonal crystal system thus has three sides. It is found as long, thin to broad prismatic and columnar crystals that are habitually triangular in cross-section.
Source – It is mined through out in the world. Minas Gerais and Bahia at Brazil are the prime source for all the varieties. Kenya, Madagascar, Mozambique, Mexico, Myanmar, Namibia, Nigeria, Afghanistan, Pakistan, Russia and Sri Lanka are few more countries that produce good amount of this gemstone. Fascinating green and lovely pink colored gemstones are procured from California, Utah and Maine State of United States of America respectively. Tanzania is rich source of chrome variety green colour.
Enhancement – A small number of pale stones are heat treated to improve its colour. Some are irradiated to enhance the overall look of the stone. Sporadically it is oiled to bury the apparent inclusions and other surface-reaching cracks.
Imitations – It is yet to be synthesized by modern methods and techniques. However, man-made imitations such as glass are frequently seen in the gemstone trade market. Also poor quality natural stones are treated to look like different varieties of tourmalines. All these and more are sold under fancy trade names to dupe the innocent buyers.
Uses – This fascinating gemstone is used for creating attractive jewelry items. Using the creative mix of varied colours of gemstone, jewelry designer produce alluring designs. Rings, earrings, pendants, broaches, back-pins, necklaces etc are created to suit the casual as well as formal attire. All jewelries are made in 14K or 18K yellow gold/white gold. Sterling silver is also widely used for making the stylish jewelry. Other than the jewelries, it used as an ornamental stone. Figures and carvings made up of this gemstone are popular in every corner of the globe.
Apart from these usual gemstones use, it is an important component in making pressure gauges, specialist microphones and electronic instrumentation. It is highly thought of by the scientist as it confers the thermal and fluid history of rocks where it is formed. Also is closely allied with several foremost metallic ore deposits, preserves chemical marks of it’s rock sources, succumbs isotopic proof for the environmental supply of the boron and is a significant link in the boron cycle. One of its unusual physical characteristics is that by heating or rubbing vigorously it gets charged. Then it shows positive charge at one end while negative at the other end. This is termed “pyro-electricity”. Due to this feature it is used to extract the ashes and dust from the pipes (Pipes used for smoking) and named as “Aschetrekker”.
Precautions – It is the hard stone having the hardness of 7-7.5 Mohs and could be used for wearing daily in earrings, rings or pendants. However, in order to endure years of wear keep it away from steam cleaning, home ultrasonic cleaner and heating. It should also be protected from scratches and sharp blows. Large temperature change is hazardous for the long-term life of the stone thus, must be avoided. Exposure to sweltering sunlight, excessive heat, acids and harsh chemical present in cosmetics and cleaning agents must be sternly avoided else the stones are ruined badly. These few precautions and care would enable the forever the brightness and glow of the gemstone.
Beliefs – In ancient time, many royal families used it in their royal jewels like Russian Crown from the 17th century had red tourmalines instead of ruby and the last Empress of China, Empress Dowager Tz’uHsi adored pink tourmaline. She had an enormous collection of this startling gemstone.
It is believed to shield the wearer in opposition to many adverse circumstances and bad luck. It inculcates the positive traits like confidence, enthusiasm, constructive thinking etc. and overcomes the negativity. It creates the balance between different energies. It is trusted to be idyllic for relationships as it fosters potent sway on love and friendship resulting in immovability and constancy.
This awe-inspiring gemstone is treasured for its multi-coloured look. The inimitable gamut of colours and plechorism flaunted by the stone makes it very special for the gemstone collectors and admirers in the entire universe. The soothing colours of the gem offer elegance and classy touch to the looks of the lady. This rainbow gemstone suits all moods and surely would fill as many its colours in your life.
|Chemical Composition||It is Complex Aluminium Borosilicate and the chemical formula is (Na,Ca)(Mg,Li,Al,Fe2+)3Al6B3Si6(OH)4.|
|Colours||Green, red, blue, yellow, brown, pink, black, colourless etc. Also bi-colours found like amazing watermelon.|
|Hardness||7 – 7.5 Mohs.|
|Refractive Index||1.616 – 1.652|
|Specific Gravity||3.03- 3.25|
|Solid State||Transparent to opaque.|
|Crystal System||Trigonal crystal system.|
|Fractures||Sub-conchoidal to uneven.|
|Cleavage||Good to poor prismatic.|
|Birefringence||Medium. Varies between 0.014 to 0.021|
|Source||Brazil, USA, Tanzania, Kenya, Madagascar, Mozambique, Mexico, Myanmar, Namibia, Nigeria, Afghanistan, Pakistan, Russia and Sri Lanka.|
|Enhancement||Often enhanced through heat treatments, irradiation and oiling.|
|Precautions||All general gemstone care and precautions.|