What Is Tourmaline Gemstone | Tourmaline Stone

Overview

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(Li_1.5,Al_1.5)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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