mineral

Black Tourmaline (Schorl)

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

Hardness: 7-7.5 on Mohs scale; Color: Jet black; Luster: Vitreous to sub-metallic; Crystal structure: Trigonal/Hexagonal with elongated prismatic crystals and vertical striations; Specific gravity: 3.0-3.25.

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

Identified June 17, 2026More mineral →

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Physical properties

Formation & geological history

Formed primarily in granitic pegmatites, hydrothermal veins, and occasionally in metamorphic rocks like schist through high-temperature fluid processes involving boron.

Uses & applications

Used in the manufacturing of pressure gauges due to piezoelectric properties, gemstone jewelry, and highly popular in the metaphysical market for 'protection'.

Geological facts

Black tourmaline is both piezoelectric (generates electricity under pressure) and pyroelectric (generates electricity when heated), a property that causes it to attract dust particles.

Field identification & locations

Identify by its deep black color, vertical striations (ridges) along the length of the crystal, and its triangular or rounded triangular cross-section. Commonly found in Brazil, Africa, and the USA.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral