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Tourmaline

Tourmalines have a wide variety of exciting colors with one of the widest color ranges of any gem.

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26.32-ct.

This 26.32-ct. oval pink tourmaline is from Mozambique.

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Rubellite

Trade name for pink, red, purplish red, and orangy red tourmaline.

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Inclusions

It’s not unusual for pink tourmalines to have eye-visible inclusions.

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California

This beautiful tourmaline mineral specimen is from California.

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Columnar Form

The specimen displays tourmaline’s characteristic columnar form.

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Fantastic Crystal

Fantastic pink tourmaline crystal with quartz with other minerals.

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Tools

Overview

About Tourmaline

about tourmaline

Tourmaline’s colors have many different causes. It’s generally agreed that traces of iron, and possibly titanium, induce green and blue colors. Manganese produces reds and pinks, and possibly yellows. Some pink and yellow tourmalines might owe their hues to color centers caused by radiation, which can be natural or laboratory-induced.

Tourmaline Description

Tourmaline History and Lore


Birthstones & Anniversaries

Tourmaline is a birthstone for October, along with opal. Tourmaline is also the gem of the eighth anniversary.

1554

Francisco Spinoza’s expedition discovers “Brazilian emerald”: the first recorded green tourmaline crystal.


Pyroelectric

Tourmaline becomes electrically charged when heated. Also when squeezed: it’s piezoelectric too.


Paraiba

Brazilian source famous for vivid blue to green tourmalines colored by copper.


Facts

  • Mineral: Tourmaline
  • Chemistry:
  • Elbaite Na(Li1.5,Al1.5)Al6Si6O18(BO3)3(OH)4
  • Dravite NaMg3Al6Si6O18(BO3)3(OH)4
  • Liddicoatite Ca(Li2Al)Al6Si6O18(BO3)3(OH)3F
  • Chromedravite NaMg3Cr6Si6O18(BO3)3(OH)4
  • Color: All colors
  • Refractive index: 1.624 to 1.644
  • Birefringence: 0.018 to 0.040
  • Specific gravity: 3.06 (+0.20, -0.06)
  • Mohs Hardness: 7 to 7.5

Treatments

There are a number of processes used to alter the color, apparent clarity, or improve the durability of gems.

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Synthetics

Some gemstones have synthetic counterparts that have essentially the same chemical, physical, and optical properties, but are grown by man in a laboratory.

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Imitations

Any gem can be imitated—sometimes by manmade materials or by natural materials chosen by man to impersonate a particular gem.

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gem love

Why We Love This Gemstone

1
Trigonal System

Tourmaline crystallizes in the trigonal system; no other common mineral has three-sided prisms.

2
Watermelon Variety

Watermelon tourmaline is green on the outside and a delicious pink on the inside.

3
Liddicoatite

Liddicoatite tourmaline was named for beloved former GIA President Richard T. Liddicoat.

Quality Factors

Tourmaline’s varieties have a wide range of quality factors considerations.

Color

quality factors

Tourmaline's rainbow colors have a wide range of color intensity and tone.

Clarity

quality factors

Pink to red tourmaline often has more visible inclusions than green to blue varieties.

Cut

quality factors

Tourmaline crystals are often long, leading cutters to cut slender finished stones.

Carat Weight

quality factors

Tourmalines come in all shapes and sizes. The value change for size varies with the variety.

Tourmaline Quality Factors: The Comprehensive Guide

Research

Explore sources, gemological research, and the role of gems in history.

Representative copper-bearing liddicoatite tourmaline from the study.

Cuprian Liddicoatite Tourmaline

Yusuke Katsurada and Ziyin Sun , Jan 30, 2017 Read Article

From Brazil to China: The Journey of Rubellite Tourmaline

Andrew Lucas , Mar 27, 2015 Read Article

Expedition to the Cruzeiro Tourmaline Mine in Minas Gerais, Brazil

Andrew Lucas, Duncan Pay, Tao Hsu, Shane McClure, and Pedro Padua , Mar 27, 2015 Read Article
Solution-Generated Pink Color Surrounding Growth Tubes and Cracks in Blue to Blue-Green Copper-Bearing Tourmalines

Solution-Generated Pink Color Surrounding Growth Tubes and Cracks in Blue to Blue-Green Copper-Bearing Tourmalines from Mozambique

John I. Koivula, Kevin Nagle, Andy Hsi-Tien Shen, and Philip Owens , Apr 6, 2009 Read Article