Tourmaline

Formula: A(D3)G6(T6O18)(BO3)3X3Z
Hardness: 7
Specific Gravity: 2.9 - 3.1
Crystal System: Trigonal

Name: Reported by Christianus-Fridericus Garmann in 1707. The name "tourmali" was a generic name used in Ceylon [Sri Lanka] for colored gems, mostly zircons. About 1703, it had been discovered by Dutch lapidaries that some of the "zircons" arriving in the Netherlands were actually a previously undescribed mineral. Several names were given to the new mineral including "Pierre de Ceylan, by Lemery in 1717. Tourmalin, as a more or less specific mineral name, was used by Rinmann in 1766. Hill called it Tourmaline Garnet in 1771 and Richard Kirwan shortened the name to "Tourmaline" in 1794.