Tour'ma-line1, n.
n. [Fr. tourmaline, It. turmalina, tormalina, N. Lat. turmalina, turmalinus, from tournamal, a name given to this stone in Ceylon.] [Written also turmaline.] (Min.) A mineral occurring usually in black three-sided or six-sided prisms, terminated by three-sided pyramids. It also presents brown, blue, green, and red colors.
☞ The blue has been called indicolite; the red, rubellite. Both the green and red varieties are highly esteemed in jewelry when clear and of a large size. The black tourmaline was formerly called schorl. Crystals of tourmaline, when heated, are remarkable for exhibiting electric polarity. Dana.