Coloured Tourmalines

Now spring is finally here, bright cheerful colours have started popping up all over which got me thinking about the many pretty types of coloured tourmalines. Being surrounded by these beautiful gemstones as often as I am it’s easy to forget how few people actually know about them. In fact there have been several occasions where customers have asked “and what’s a tourmaline?” So I thought I would take this opportunity to tell you a little about them.

There are many types of tourmaline, these different types relate to their colour – of which there are many different ones. But they all have the same properties, a triagonal crystal structure with elongated prismatic crystal. With the gem quality, tourmalines that are used today come mainly from the Elbaite mineral species, which exhibits the strongest and brightest colours of all tourmaline mineral species. Other mineral species include; dravite, uvite, olenite, schorl, liddiccatite and buergerite. Tourmalines are dichromatic gemstones, this is where a bright colour is shown from one direction but will look almost black when seen from the other side, and this is something that has to be taken into consideration when the stones are being cut to produce the best results. It has hardness 7 – 7.5 on the Mohs scale which means that they are good alternative for engagement rings. However care does need to be taken into consideration with stones with lots of inclusions or bi coloured stones as these factors are weak points with-in the stones.

Popular tourmaline colours

As mentioned previously there are many different types of tourmaline and this is just a little about the more common and also more interesting verities. The most commonly known is verdilite which can vary from a yellow / blue-ish green. A much rarer type of green tourmaline is a chrome tourmaline which is much closer in colour to an emerald, the yellow forms of tourmaline are known as “Canary tourmaline”. Tourmalines also come in a range of pinks to reds which can also be brownish, orangey or purplish and are known as Rubellite. A tourmaline that is more violet with green or blue tones is known as an Indicolite. Another rare and very collectable type of tourmaline is known as Paraiba, which was being produced in a modest quantity for a short time. The vivid colour comes from the copper impurities and they were considered so unique they revolutionized the tourmaline business with the demand for all tourmalines benefiting from their success since the late 1980’s when the cuprain elbaites where first discovered. There are also some very interesting types of tourmaline that show more than one colour such as Watermelon tourmalines which are tourmaline crystals with a pink centre and green rim, or vice-versa, hence the name! The causes for the colour in the stone comes from the traces of other minerals found with-in them; blue colouring is caused by iron, red & pinks come from the traces of manganese and some titanium and green colouration is caused by a combination of iron, chromium and vanadium.

Like topaz, tourmalines hold static electricity when rubbed or gently heated; this is one way that they can be identified. In the early 1700’s traders from Holland brought tourmalines into Europe from Sri Lanka. These traders were fascinated with the electrical properties of the stone, those whom smoked pipes thought tourmalines held magical abilities as when the stones were heated they would draw the ashes from out of their pipes, they gave the stone the name aschentracken meaning “ask puller”. This magnetic and magical abilities were later scientifically determined as a unique piezoelectric and pyroelectric properties found within the stone. Simply this electric charge is due to the heat in the stone creating positive and negative charges at the ends of the crystals. The name tourmaline is said to come from the Sanskrit word “turamali” but is also said to come from the Sinhalese word “turmalali” meaning mixed coloured.