Tourmaline (TUR-mə-leen) is a crystal boron silicate mineral compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. Tourmaline is classified as a semi-precious stone and the gemstone comes in a wide variety of colors.

Brightly colored Sri Lankan gem tourmalines were brought to Europe in great quantities by the Dutch East India Company to satisfy a demand for curiosities and gems. At the time it was not realised that schorl and tourmaline were the same mineral (it was only about 1703 that it was discovered that some colored gems weren’t zircons). Tourmaline was sometimes called the “Ceylonese [Sri Lankan] Magnet” because it could attract and then repel hot ashes due to its pyroelectric properties.[2][3]

Tourmalines were used by chemists in the 19th century to polarize light by shining rays onto a cut and polished surface of the gem. [Source: Wikipedia]