mineral

Black Tourmaline

Schorl (Sodium iron aluminum boron silicate hydroxide)

AI-generated identification · may be incorrect

Hardness: 7 to 7.5 on Mohs scale; Color: Deep black, opaque; Luster: Vitreous to sub-metallic; Crystal Structure: Trigonal (often long, columnar); Cleavage: Indistinct; Specific Gravity: 3.0 to 3.25

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

Identified July 13, 2026More mineral →

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Physical properties

Hardness: 7 to 7.5 on Mohs scale; Color: Deep black, opaque; Luster: Vitreous to sub-metallic; Crystal Structure: Trigonal (often long, columnar); Cleavage: Indistinct; Specific Gravity: 3.0 to 3.25

Formation & geological history

Forms primarily in granites and granite pegmatites, as well as in metamorphic rocks like schists and marbles through hydrothermal processes.

Uses & applications

Used widely in metaphysical/spiritual communities for protection, industrially for its pyroelectric properties in pressure gauges, and occasionally in jewelry as beads or cabochons.

Geological facts

Tourmaline is pyroelectric and piezoelectric, meaning it can generate an electrical charge when heated or mechanically stressed. Schorl is the most common member of the tourmaline group, making up 95% of all tourmaline in nature.

Field identification & locations

Identify by its deep black color, vertical striations (furrows) along the length of the crystals, and a triangular or rounded triangular cross-section. Found globally, with notable deposits in Brazil, Africa, and the USA.