What it is confused with
Glass, and historically emerald and ruby: green tourmaline was sold as "Brazilian emerald". Tourmaline looks darker when viewed down the length of the crystal.
Every color; often several in one crystal
Tourmaline crystals
Tourmaline is complex boron silicate with variable aluminum, iron, magnesium, lithium, every color; often several in one crystal, rated 7–7.5 on the Mohs scale. Traditionally, it is associated with protection and grounding, especially the black variety — attributed, not demonstrated.
- Mohs hardness
- 7–7.5 scratches window glass
- Crystal system
- Trigonal
- Main sources today
- Brazil also Nigeria, Mozambique
Is Tourmaline a birthstone?
Yes. Tourmaline is the modern birthstone for October.
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Properties
Composition
Complex boron silicate with variable aluminum, iron, magnesium, lithium
Hardness (Mohs)
7–7.5
Crystal system
Trigonal
Color
Every color; often several in one crystal
Mined in
Brazil, Nigeria, Mozambique, Afghanistan, USA (Maine)
Worth knowing
Tourmaline develops an electric charge when heated or squeezed. Watermelon tourmaline grows pink at the core and green at the rim.
History
Dutch traders in the 1700s noticed it attracted ash when warmed — the pyroelectric effect.
Buying
Buying Tourmaline: fakes, value and treatments
What decides the price
Neon blue-green copper-bearing Paraíba tourmaline, discovered in Brazil in the 1980s, is by far the most expensive. Bi-colored "watermelon" slices are popular with collectors.
Where it is used
Its piezoelectric property made it useful in early pressure gauges.
A less familiar fact
"Caesar's Ruby", a pendant once owned by Catherine the Great, is actually a red tourmaline.
Practical
Caring for Tourmaline
How to clean it
Warm soapy water. Avoid ultrasonic if the stone has inclusions, which many do.
How to tell it is real
Genuine tourmaline is pyroelectric — warm it and it attracts dust and small paper fragments. Glass does nothing.
How hard is Tourmaline?
Tourmaline is just harder than quartz and tough enough for rings. Its weak point is inclusions, which many stones have and which an ultrasonic cleaner can stress. Among the stones in this reference, the next softer is Garnet (6.5–7.5) and the next harder Aquamarine (7.5–8).
Tourmaline, at 7–7.5, is harder than 34 of the other 42 stones here and softer than 8.
Traditional associations
Tourmaline is traditionally associated with protection and grounding, especially the black variety. Chakra in crystal practice: Varies by color — black for Root, pink for Heart. Element: Earth.
Questions about Tourmaline
What is Tourmaline made of?
Complex boron silicate with variable aluminum, iron, magnesium, lithium, crystallizing in the trigonal system.
Which month is Tourmaline the birthstone for?
October.
Where does Tourmaline come from?
Brazil, Nigeria, Mozambique, Afghanistan, USA (Maine).
Can Tourmaline be worn every day?
Yes. It rates 7–7.5 on the Mohs scale, and the main thing to watch is ultrasonic cleaning of included stones.
Cite this page
AstroHot. “Tourmaline Crystals: Meaning, Hardness and Origins.” Accessed October 28, 2026. https://astrohot.com/crystals/gemstones/tourmaline/
For Wikipedia
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