mineral

Black Tourmaline (Schorl)

Schorl (NaFe2+3Al6(Si6O18)(BO3)3(OH)3OH)

AI-generated identification · may be incorrect

Hardness: 7-7.5. Color: Black. Luster: Vitreous to sub-metallic. Crystal structure: Trigonal/Hexagonal. Cleavage: Indistinct. Specific gravity: 3.0-3.2.

Hardness: 7-7
Color: Black
Luster: Vitreous to sub-metallic

Identified July 6, 2026More mineral →

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Physical properties

Hardness: 7-7.5. Color: Black. Luster: Vitreous to sub-metallic. Crystal structure: Trigonal/Hexagonal. Cleavage: Indistinct. Specific gravity: 3.0-3.2.

Formation & geological history

Part of the tourmaline group, it typically forms in granitic pegmatites, hydrothermal veins, and metamorphic rocks like schists. It is a boron-rich silicate mineral commonly associated with quartz and feldspar.

Uses & applications

Used as an industrial abrasive, in pressure gauges due to its piezoelectric properties, but most commonly used as a protective stone in jewelry and metaphysical collections.

Geological facts

Schorl accounts for approximately 95% of all tourmaline found in nature. It is strongly pleochroic and exhibits both pyroelectric and piezoelectric properties, meaning it can generate an electrical charge when heated or compressed.

Field identification & locations

Identify in the field by its characteristic elongated, striated black crystals that often have a triangular or hexagonal cross-section. It is common in pegmatite-rich areas like those in Brazil, Pakistan, and the USA (California and Maine).