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CHAPTER XX
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TOURMALINES
A STONE of many colours is tourmaline; it was introduced into Europe from India in 1703 and its name is adapted from turmali, its
Cingalese name. Tourmaline is a widely distributed mineral, and its
transparent coloured varieties, used as gem stones, have attained a
considerable popularity. The vogue of the tourmaline has increased
since it was discovered in 1820 on Mount Mica near Paris, Maine. The
tourmaline has also been found in Massachusetts, California,
and New York State. Its principal sources are Ceylon, Burma, Brazil,
and the Ural Mountains, Siberia; it is also found in Moravia, Sweden,
and the Isle of Elba. Tourmaline occurs in granite, particularly
the albitic varieties, schists, and dolomite. Crystallisation of the
tourmaline is rhombohedral, hemi-morphic, and the prisms have three,
six, nine, or twelve sides. In hardness it is equal to quartz
and approaches topaz, being 7 to 7.5. Its lustre
160
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