The name tourmaline comes from the Sinhalese tura mali, meaning “stone of mixed colours.” With its wide range of colours spanning the full spectrum, from pale peachy pink to bright blue, forest green, vivid yellow and through to deep red, tourmaline stands apart from other gemstones – ancient legend relates that as tourmaline journeyed to the surface of the earth it passed over a rainbow and picked up its colours.
Understandably tourmaline was historically confused with other gems, in the 1500’s a Spanish conquistador found green tourmaline in Brazil and thought it was emerald. The stone’s crystal composition made of aluminium boron silicate accounts for its wide colour range, since no two of these crystals are the same an enormous number of nuanced hues and shades is possible. Only as recently as 1793 was tourmaline finally identified as its own mineral species, with different chemical compositions and physical properties, and many resulting varieties having their own names.
A spike in popularity resulted from the exploitation of American tourmaline deposits, in 1876 mineralogist George Kunz sold green tourmaline from Maine to Tiffany & Co., and a craze for the gem ensued. In the early 1890s tourmaline was found in California, although for many centuries Native Americans had been giving certain colours of tourmaline as funeral gifts. At this time China was the biggest consumer, the Chinese Empress Dowager Cixi was particularly fond of pink tourmaline and purchased large quantities of deposits from San Diego County – between 1902-10 120 tons of gem-grade material were mined at Mesa Grande. Demand for tourmaline in China was crucial to the health of the overall market, it was used here in snuff bottles, carvings, jewellery and other precious objects and when the Chinese government collapsed in 1912 the trade in tourmaline took a downward turn with it.
Tourmaline in all colours is found in Brazil, however discoveries there in the 1980s and ‘90s reignited interest in the gem, with material mined in Paraíba displaying striking neon greens, radiant blues and vivid violets, due to the presence of trace elements copper and manganese. The high value of the rough stone found here means that stones are often custom cut, with brilliant-cut, pear and oval shapes the most popular. The world’s largest cut tourmaline was found in Paraíba, the large bluish-green tourmaline weighing 191.87 carats was unveiled in Toronto in 2009. Copper-bearing tourmaline in similar colours is also found in Nigeria and Mozambique although only that found in Brazil is known as ‘Paraíba tourmaline’.
On the Mohs scale of hardness tourmaline is ranked at 7-7.5, which makes it well suited to taking on a high degree of polish. Many tourmaline crystals exhibit polarity, meaning that the colour, electrical properties and the crystal forms are different at either end of the crystal, this is down to the complex structure and chemistry of the stone. When heated or rubbed, tourmaline acquires an electric charge and can attract dust or light items, this property is known as ‘pyroelectricity’, and was first recorded as a scientific phenomena in the 18th century by the Swedish botanist Carl Von Linne.
Although available in many colours, typically the red and green varieties are the most seen, with red tourmaline also known as rubellite and green tourmaline called verdilite. Rubellite when very fine is easily mistaken for ruby and its price has increased significantly in recent years. One of the largest stones in the Russian Crown Jewels, considered to be a ruby and named ‘Caesar’s ruby’, has now been identified as a red tourmaline. Verdilite green tourmaline can be highly saturated in colour, with two shades of green, bluish and yellowish, revealed as the stone is turned, this variety is highly valuable too. Watermelon zoning is the phenomena whereby a stone ranges in colour from pink in its interior to a green exterior, brought about by variations in the concentration and composition of trace elements present during the growth of the crystal. Jewellery designers often use slices of the crystal to display the watermelon effect rather than a faceted stone created from the rough.
Tourmaline was favoured by many modern and contemporary jewellers, notably René Boivin, Suzanne Belperron, Jean Schlumberger and Andrew Grima. They used tourmaline in abundance with smaller, better-known gem stones and but also by itself across the range of its hues. The palette offered by tourmaline was particularly suited to the ground-breaking, quirky designs of Grima of the 1960s and 70s. These pieces invariably feature a single tourmaline stone in a setting fashioned to accommodate and showcase the unique qualities of the stone. The market for jewels from this era is growing, although currently there is still scope to acquire an impressive tourmaline at a competitive price.
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