Tourmaline crystalizes in the form of vertically striated prismatic crystals, sometimes slender and sometimes needle-like. The colour range includes deep pink to red-violet (Rubellite, blue to indigo-blue (Indicolite), yellow (also known as "Peridot of Ceylon" and as Tsilasite), brown (Dravite), green, pink, (Elabaite), orange, purple/lavendar, black (Aphrizite and Schorl), colourless (Achroite), bi-coloured, tri-coloured, multi-coloured, and a variety which exhibits triangular and triskelion formations when sliced perpendicular to the c-axis (Liddicoatite).
The mineral was first reported by J.D. Dana (as Turmalin) in 1837 and is said to be a corruption of the Sinhalese word "turmali" which was applied by Sri Lankan jewelers to describe yellow Zicron, and was subsequently, mistakenly applied to a consignment pf Tourmaline which was sent to Amsterdam; the name stayed and Tourmaline became a group of minerals.
The general composition is reported as:
"Tourmaline is of comparatively modern origin in Europe as far as its use as a precious stone is concerned. It is very remarkable because of its electrical qualities, for when heated one end will become positive and attract straws or ashes, whilst the other end will be negative and non-attractive.
It is transparent in one direction, but if looked at from another it may be found quite opaque.
It is found in India, Siberia, Brazil, and America, and of all colours and shadings of red, pink, yellow, green, and white; two colours may also exist on the same crystal, which may be green at one end and red at the other. This is probably the stone Pliny describes as the Lychnis, which, being very susceptible to solar influences, attracted small particles of chaff when heated by the sun, and had the power of "dispersing fears and melancholic passions." It was also worn to procure inspiration, to attract favours, and to secure friends."
-The Book of Talismans, Amulets and Zodiacal Gemsby William Thomas and Kate Pavitt 1922