mineral

Black Tourmaline (Schorl)

Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)

AI-generated identification · may be incorrect

Hardness: 7-7.5 on Mohs scale; Color: Jet black, sometimes with brownish or rusty surface staining; Luster: Vitreous to sub-metallic; Crystal structure: Trigonal/Hexagonal with vertical striations (grooves); Cleavage: Indistinct; Specific Gravity: 3.0-3.25.

Hardness: 7-7
Color: Jet black, sometimes with brownish or rusty surface staining
Luster: Vitreous to sub-metallic

Identified June 17, 2026More mineral →

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Physical properties

Formation & geological history

Formed primarily in pegmatites through hydrothermal processes. It occurs during the final stages of granitic magma crystallization where boron and iron are concentrated. Can be found in igneous and metamorphic rocks.

Uses & applications

Used extensively as a healing stone in the metaphysical community, for electrical industrial purposes due to its piezoelectric properties, and sometimes as a minor ore of boron. Lower quality specimens like this are used for collection or grounding displays.

Geological facts

Black tourmaline is both piezoelectric (generates electricity under pressure) and pyroelectric (generates electricity when heated). It was historically used by Dutch traders to pull ash out of their meerschaum pipes, earning it the nickname 'Aschentrekker' (ash puller).

Field identification & locations

Identify in the field by its distinct columnar crystals with vertical striations, triangular cross-section, and lack of cleavage. It is commonly found in Brazil, Namibia, Pakistan, and the United States (California, Maine).