Tourmaline

Tourmalines are precious stones with an instant and colourfully vibrant appeal and also known as the ’Gemstone of the Rainbow’. They derive their name from the Singhalese term ’tura mali’ that loosely translates to ’stone with mixed colours’.

Chemically, they are mixed crystals of aluminium boron silicate with a complex and variable composition. They belong to the trigonal crystal system and occur as long, trim to chunky columnar and prismatic crystals. Blue tourmalines are gemstones with greenish blue tones of outstanding brilliance. However, it is rare to come across a pure blue tourmaline. They certainly are exceptionally prized owing to their beauty and rarity. Besides blue, tourmalines exhibit a wide array of colours. Black tourmalines are the ones with generous amounts of iron in them, while the brown and yellow variants owe their tint to magnesium. Some of them may be green at one end while pink at the other, or green on the periphery and pink in the middle. Such gems are known as ’Watermelon Tourmalines’.

It is not uncommon for a tourmaline to possess two or more colours. Some change their colour when the lighting changes and some even show the effect of a cat’s eye. Another feature is the marked dichroism where the colour changes happen depending on the angle of viewing.

One highly admired type is the Paraiba tourmaline, found in Mina da Batalha in the Brazilian State of Paraiba. Their lively turquoise to green tones are such as not found in perhaps any other gemstone in the world.