For centuries Tourmaline has been a gemstone that has been collected and admired for it’s almost infinite array of colours. Most people will know of Tourmaline as being a green or red gemstone with the most common source being from Brazil. Recent deposits have been found in Madagascar and Africa that have redefined the definition of possible colours that this gemstone can come in. The Brazilian Tourmaline can come in beautiful rich greens as well as vivid pinkish red stones. The pinkish red version has been named “Rubellite”.
Tourmaline is relatively hard coming in at 7 – 7.5 on the MOHS scale. This is an important attribute in any gemstone because it shows how resistant the gem is to scratching. Since Tourmaline is so hard it lends itself to being worn ever day without the worry of scratching and damaging.
Brazil also produces these amazing little “Rubellite eyes”, which are composed of pink Tourmaline with a small amount of black Schorl.
Collectors often try to find “Watermelon Tourmaline” which as the name suggests looks just like a watermelon. It has a green outer ring with a pink middle. These can be set into pendants in the rough and they look great.
In recent times, the now famous Paraiba Tourmaline was discovered in Paraiba, Brazil. This stunning stone is coloured by Copper and the colour is so unique. If you ever get to see one of these in person you will be amazing at how much it glows.
Since the gemstone mining boom in Africa began, deposits of this rare stone have been found in Madagascar. These stones are slightly different in colour and usually have to be heat treated to reach their final colour.
Other African mines in Kenya and Nigeria are also producing a nice green colour sometimes referred to as Chrome Tourmaline.
Probably the most significant find in Africa is the Namibian deposits. These deposits have produced the most amazing colours I have ever seen in Tourmaline. I am glad that most of the gems you see from this area are well cut and really show off the brilliance of the gem.
Tourmaline is actually the name given to multiple individual minerals. The main type of Tourmaline you will see with bright colours is the Elbite Tourmaline. The brown coloured stones are called Dravite and the black stones are Schorl. Tourmalines with a blue hue are generally called indicolite:
- Crystal Structure: Trigonal
- Color: Colourless through to Black with almost every combination in between.
- Hardness: 7 to 7.5 on the Mohs scale (what does this mean?)
- Refractive Index: 1.624 to 1.644
- Density: 3.06
- Cleavage: Indistinct
- Transparency: Transparent to opaque
- Double Refraction or Birefringence: -0.018 to -0.040
- Luster: Vitreous
- Fluorescence: Weak: Red to Violet
Famous Tourmaline Gemtones
Two of the largest Tourmalines that are worth mentioning are the 191.87cts Paraiba Tourmaline and the 376.85cts Tourmaline carving by O. Hansen.
The 191.87cts Pariaba Tourmaline comes from Mozambique and has incredible colour. This is one of the most important Tourmaline gemstones ever found. [/one_half]
This is one of the most unique and beautiful Tourmalines ever discovered. It is opaque which has made it perfect for carving. The result now sits in the National Museum of Natural History
Buying Guide For Tourmaline
Tourmaline is a tricky gemstone to buy because there are so many rules to follow. In most cases, the gem should be clear of eye visible inclusions because they can detract from the value. However, when talking about Rubellite and Paraiba Tourmaline, because they are so rare, inclusions are ok.
- Colour – Look for stones that don’t have too much darkness in them. The brighter the colour the more valuable to stone will be.
- Clarity – With the exception of Rubellite and Paraiba Tourmaline, look for stones that are at least eye clean.
- Carat size – Bigger the better. Large Tourmalines are not uncommon, but finding large stones with good colour is the tricky part.