tourmaline

American  

[toor-muh-lin, -leen] / ˈtʊər mə lɪn, -ˌlin /

Also tourmalin

noun

1. 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.

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tourmaline British  

/ ˌtʊəməˈlɪnɪk, ˈtʊəməˌliːn /

noun

1. 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

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tourmaline Scientific  

/ tr′mə-lĭn,-lēn′ /

1. Any of several minerals having the general chemical formula (Na,Ca)(Mg,Fe,Al,Li) ₃ Al ₆ (BO ₃ ) ₃ Si ₆ O ₁₈ (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.

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Usage

What does tourmaline mean? Tourmaline is a mineral that is commonly black but also has transparent, colored varieties considered gemstones, including in pink and green.Tourmaline varies in composition and is typically categorized into three types: iron tourmaline (a black variety, also called schorl), magnesium tourmaline (a brown variety, also called dravite), and alkali tourmaline.As a gemstone, tourmaline is classified as semiprecious, a label given to gemstones that are not as valuable as those considered precious. Tourmaline is generally inexpensive due to its abundance, but certain varieties are more expensive, such as those from Paraiba, Brazil, which are valued for their color saturation.Tourmaline is one of the birthstones for the month of October. It is associated with the zodiac signs Libra and Scorpio. It is also the gem designated for an eighth wedding anniversary.Tourmaline has the ability to become electrically charged when heated and is also used in electrical equipment.Tourmaline can also be spelled tourmalin and turmaline.Example: Many people mistake the red tourmaline stone in my ring for a ruby.

Other Word Forms

• tourmalinic adjective

Etymology

Origin of tourmaline

1750–60; earlier tourmalin < German Turmalin, ultimately < Sinhalese tōramalliya “carnelian”; -in ²

Example Sentences

Like obsidian, in fact, their edges are sharp but the shards have an almost twirly shape and lack the crystalline structure of black-colored minerals like augite or tourmaline.

From Salon • Mar. 4, 2025

Then we each get a piece of black tourmaline, considered a so-called “grounding stone” that is said to offer protection.

From Los Angeles Times • Nov. 29, 2023

Campbell Bridges had a long relationship with the Smithsonian that began in 1967, when he traded some of his tanzanite specimens to the museum for some of its tourmaline collection, Bruce Bridges said.

From Washington Post • Apr. 19, 2023

Pink sapphire, rose quartz, star ruby, rhodonite, rubellite, pink tourmaline and — last but certainly not least — pink diamonds.

From Seattle Times • Nov. 17, 2022

Clenching her jaw to keep herself from snapping at him, Sefia took her coin purse from the inner pocket of her vest and withdrew the uncut tourmaline.

From "The Reader" by Traci Chee