Tourmaline

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Tourmaline ( /ˈtʊərməln/ TOOR-mə-leen) is a crystalline 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.

According to the Madras Tamil Lexicon[3] the name comes from the Sinhalese word "thoramalli" (තෝරමල්ලි) or "tōra- molli", which is applied to a group of gemstones found in Sri Lanka. According to the same source, the Tamil "tuvara-malli" (துவரைமல்லி) and "toramalli" are also derived from the Sinhalese root word. This etymology is also given in other standard dictionaries including the Oxford English Dictionary.

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,[when?] it was not realised that schorl and tourmaline were the same mineral, as it was only about 1703 that it was discovered that some colored gems were not zircons.[citation needed] Tourmaline was sometimes called the "Ceylonese Magnet" because it could attract and then repel hot ashes due to its pyroelectric properties.[2][4]

Tourmalines were used by chemists in the 19th century to polarize light by shining rays onto a cut and polished surface of the gem.[5]

Commonly encountered species and varieties:

Schorl species:

Dravite species: from the Drave district of Carinthia

Elbaite species: named after the island of Elba, Italy

This page was last edited on 23 June 2018, at 12:30 (UTC).
Reference: https://en.wikipedia.org/wiki/Tourmaline under CC BY-SA license.

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