mineral

Schorl (Black Tourmaline) in Matrix

Sodium Iron Aluminum Borosilicate Hydroxide (NaFe2+3Al6Si6O18(BO3)3(OH)3OH)

Hardness: 7-7.5 (Mohs); Color: Jet black; Luster: Vitreous to sub-metallic; Crystal structure: Trigonal/Hexagonal columns; Cleavage: Indistinct; Specific Gravity: 3.0-3.2

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

Identified April 1, 2026More mineral →

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Physical properties

Hardness: 7-7.5 (Mohs); Color: Jet black; Luster: Vitreous to sub-metallic; Crystal structure: Trigonal/Hexagonal columns; Cleavage: Indistinct; Specific Gravity: 3.0-3.2

Formation & geological history

Formed in granitic pegmatites, hydrothermal veins, and occasionally metamorphic rocks like schists during the cooling of molten magma or mineral-rich hot fluids.

Uses & applications

Primarily used as a collector specimen, in metaphysical/energy healing practices, and occasionally crushed for industrial uses in pressure sensors due to its piezoelectric properties.

Geological facts

Tourmaline is unique because it is both piezoelectric (generates electricity under pressure) and pyroelectric (generates electricity when heated). Schorl is the most common variety of tourmaline, making up about 95% of all tourmaline found in nature.

Field identification & locations

Identify by its characteristic vertical striations (lines) along the length of the black crystal and its triangular cross-section. Commonly found in Brazil, Namibia, and the United States (California/Maine).

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