mineral

Black Tourmaline (Schorl)

Schorl (Sodium Iron Aluminum Borosilicate Hydroxide), NaFe2+3Al6(Si6O18)(BO3)3(OH)3OH

AI-generated identification · may be incorrect

Hardness: 7-7.5 on Mohs scale; Color: Jet black, opaque; Luster: Vitreous to sub-metallic; Crystal Structure: Trigonal (often hexagonal/columnar with vertical striations); Cleavage: Indistinct; Specific Gravity: 3.0-3.2

Hardness: 7-7
Color: Jet black, opaque
Luster: Vitreous to sub-metallic

Identified March 18, 2026More mineral →

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Physical properties

Formation & geological history

Formed primarily in pegmatites through hydrothermal processes and late-stage magmatic crystallization. It is also found in metamorphic rocks like schists. Geologically, specimens can range from hundreds of millions to billions of years old.

Uses & applications

Primarily used as a minor ore of boron, in scientific instruments for its piezoelectric and pyroelectric properties, and extensively in jewelry and metaphysical collecting.

Geological facts

Black tourmaline is both piezoelectric (generates electricity when under pressure) and pyroelectric (generates electricity when heated). It was historically used by Dutch traders to pull ash out of their Meerschaum pipes.

Field identification & locations

Identify in the field by its distinct columnar shape with vertical striations (grooves) along the crystal faces and its characteristic rounded-triangular cross-section. Commonly found in Brazil, Namibia, and the USA (California and Maine).