Tourmaline
  • Mineral: Corundum            

  • Main Source of Origin: Brazil, Namibia, Mozambique, Nigeria

  • Mohs Hardness: 7.5          

  • Birthstone: October

Tourmaline is also known as an ‘Electric Stone’ (電気石) in Japanese, which was a name given to describe its unique quality of pyroelectric and piezoelectric that means it produces static electricity with heat treatment and polishing. You can test that out by vigorously rubbing to warm up the tourmaline which will allow it to magically attract nearby bits of paper and dust or make your hair stand. Perhaps this spooky quality of tourmaline makes it a perfect birthstone for the month of October.

 

Well known for its wide range of colors that covers an extensive color spectrum, specific colors of tourmaline comes with prefixes that serves to evoke images of the hues associated, such as the vivid pink of Rubellite Tourmaline, and the striking yellow of Canary Tourmaline resembling the yellow feathers of a canary. Tourmalines of clear blue and green hues are also widely favoured. Tourmaline’s colours are a result of different elementary minerals. Iron-rich tourmalines are black to bluish-black to deep brown, while magnesium-rich varieties are brown to yellow, and lithium-rich tourmalines are almost any colour of green, blue, red, yellow, pink and more. Very rarely, colourless tourmaline can be found.

 

Today, gemologists divided tourmalines into 11 different species depending on their properties and chemical composition. While the red or pink colours are known as rubellites, blue colours are called indicolite and the multi-coloured tourmaline along with Paraiba tourmaline are called Elbaites.

Bi-colour Tourmaline

Apart from the usual single hue tourmalines, there are also bi-colour tourmaline which contains two colours. The Watermelon Tourmaline is a popular bi-color tourmaline that resembles the cross section of a watermelon. Watermelon Tourmaline was first discovered in Brazil in the 16th century in which the green crystals were initially confused with emerald. It was not until the 19th century that the gem was classified as tourmaline. Tri-colored tourmaline also exist commonly which may be green at one end, colourless in the middle and reddish-pink at the other. Some forms of tourmaline are dichroic, such that when viewed from different directions, the gemstone changes colour.

Different varieties of tourmaline tend to have different clarities. While large clean tourmalines are usually blue and bluish-green in color, almost all red and pink tourmalines show eye-visible inclusions such as fractures that appears like imperfect cracks within the gemstone. These fractures however are viewed positively as a natural characteristic of the Watermelon Tourmaline that perfectly mimics the rind and flesh of our favourite summer fruit.

Pink Tourmaline (Rubellite)

Pink Tourmaline which is a variety of tourmaline known in the trade as rubellite is one of the most sought-after tourmalines that comes in similar shades to the precious ruby. Representing a love of humanity and humanitarianism, pink tourmaline is worn with the believe to promote sympathy towards others. It has been suggestively considered by healers, therapists and counsellors as an excellent stone to disperse emotional pain, disruptive feelings and encourage unconditional love and friendship.

 

Another popular tourmaline would be a Cat’s Eye Tourmaline that has minute inclusions in the gem which gives it an appearance of a cat’s eye. The scientific explanation for this is pleochroism, an optical phenomenon caused by how light wavelengths are absorbed and bent differently as they pass through the gemstone. The following are varieties of tourmaline with specific prefixes(s):

  • Rubellite – red

  • Indicolite – blue

  • Chrome– intense green coloured by chromium/vanadium

  • Bi-Color – tourmalines which display two or more colours in the same stone

  • Watermelon – Bi-color tourmalines which show a green skin and a red core; these are often cut as slices

  • Canary – bright yellow tourmaline from Malawi

  • Paraíba– intense blue to green from Paraíba, Brazil, colorued by copper

  • Cat's Eye – chatoyant tourmaline in a variety of colours

  • Color-Change – changes from green in daylight to red in incandescent light

Together with Opal, tourmaline is also listed as an alternative birthstone for the month of October. However, noting that tourmaline has a higher score of 7 - 7.5 on the Mohs hardness scale as compared with opal (5.5 - 6.5), it has been considered more ideal for birthstone jewelry which is preferably durable for frequent wear. Another design attribute resulting from the difference on the hardiness of both stones would be while pink tourmaline can be faceted for more traditional jewelry settings, opals are best polished and smooth to prevent chipping and speeding of wear and tear.

Other information:

  • Zodiac birthstone for Virgo, Libra

  • Stone for eighth anniversary