- any of a group of silicate minerals of complex composition, containing boron, aluminum, etc., usually black but having various colored, transparent varieties used as gems.
Origin of tourmaline
Examples from the Web for tourmaline
Historical Examples of tourmaline
The "Tourmaline's" men appeared highly delighted at our defeat.In Eastern Seas
J. J. Smith
This plate of tourmaline can be turned round by the observer.The Story of the Heavens
Robert Stawell Ball
I can't resist this tourmaline, and have carried it off with me.Chats in the Book-Room
Horace N. Pym
Rutile is much lighter, 4·2, and the streak light-brown; tourmaline is only 3·2.Getting Gold
J. C. F. Johnson
Of these minerals, beryl, garnet and tourmaline are the most abundant.The Wonder Book of Knowledge
- any of a group of hard glassy minerals of variable colour consisting of complex borosilicates of aluminium with quantities of lithium, sodium, calcium, potassium, iron, and magnesium in hexagonal crystalline form: used in optical and electrical equipment and in jewellery
Word Origin for tourmaline
complete silicate of aluminum and boron, 1759, ultimately from Sinhalese toramalli, a general name for cornelian.
- Any of several minerals having the general chemical formula (Na,Ca)(Mg,Fe,Al,Li)3Al6(BO3)3Si6O18(OH)4. Tourmaline occurs in many different translucent colors, usually in crystals shaped like 3-, 6-, or 9-sided prisms. It occurs in igneous and metamorphic rocks, especially in pegmatites.