Black Tourmaline
Also Schorl
The commonest tourmaline, and the one that pulled ash from pipes.
- Family
- Tourmaline
- Formula
- NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄
- Mohs
- 7 to 7.5
- System
- Trigonal
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Science
Schorl is iron-rich tourmaline, forming striated black prisms with a rounded-triangular cross-section. Tourmaline is pyroelectric and piezoelectric: it develops opposite charges at either end when heated or squeezed.
- Mineral
- Tourmaline (variety)
- Formula
- NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄
- Crystal system
- Trigonal
- Mohs hardness
- 7 to 7.5
- Specific gravity
- 3.10 to 3.25
- Refractive index
- 1.635 to 1.675
- Lustre
- Vitreous
- Colours
- Black
Composition
NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄. Made of Sodium, Iron, Aluminium, Boron, Silicon, Oxygen, Hydrogen.
Origin
- Brazil
- Pakistan
- Namibia
- United StatesMaine, California
- Madagascar
- Nigeria
Filled dots are primary sources
Rarity
The most abundant tourmaline by far, in granites and pegmatites worldwide.
- 1 Abundant
- 2 Common
- 3 Uncommon
- 4 Rare
- 5 Exceptional
Hardness
Black Tourmaline sits at 7 to 7.5 on the Mohs scale. It will scratch glass and holds a polish in daily wear.
Energy
Associations from crystal-healing tradition, recorded here as folklore. They are not medical claims.
Chakras
- Root
Element
- Earth
Zodiac
- Capricorn
- Libra
- Scorpio
Planets
- Saturn
Properties
- Protection
- Grounding
- Boundaries
- Absorbing negativity
Lore
Dutch traders in the 1700s used heated tourmaline to pull ash from their meerschaum pipes, naming it aschentrekker. The name tourmaline is from the Sinhalese turmali, 'mixed stones'.
In modern practice it is the standard protective stone, placed at doors and desks; the association follows directly from its physical property of attracting charged particles.
- PyroelectricHeating builds an electric charge at the crystal ends.
- StriationsDeep lengthwise grooves distinguish it from black obsidian or onyx.