mineral

Black Tourmaline

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

Hardness: 7-7.5 (Mohs scale), Color: Jet black, Luster: Vitreous to resinous, Crystal Structure: Trigonal/Hexagonal, Cleavage: Indistinct, Specific Gravity: 3.0-3.2

Hardness: 7-7

Identified July 8, 2026More mineral →

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Physical properties

Hardness: 7-7.5 (Mohs scale), Color: Jet black, Luster: Vitreous to resinous, Crystal Structure: Trigonal/Hexagonal, Cleavage: Indistinct, Specific Gravity: 3.0-3.2

Formation & geological history

Commonly formed in granitic pegmatites, hydrothermal veins, and metamorphic rocks like mica schists. It is formed during the late stages of magma crystallization where boron and water are concentrated. Ages vary globally.

Uses & applications

Primarily used for metaphysical and decorative collecting. Industrially, its piezoelectric and pyroelectric properties have niche uses in high-pressure gauges and scientific sensors.

Geological facts

Black tourmaline (Schorl) makes up over 90% of all tourmaline found in nature. It was used as far back as the 18th century by Dutch traders to pull ash out of their smoking pipes due to its static-electric properties when heated.

Field identification & locations

Identify in the field by its distinct vitreous/glassy black color, vertical striations on crystal faces, and a triangular-to-rounded cross-section. It is common in gem-rich regions of Brazil, Namibia, and California.