mineral

Black Tourmaline

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

Hardness: 7 to 7.5; Color: Deep black, opaque; Luster: Vitreous to sub-metallic; Crystal structure: Trigonal/Hexagonal; Cleavage: Indistinct; Specific Gravity: 3.0-3.2

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

Identified July 19, 2026More mineral →

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Physical properties

Hardness: 7 to 7.5; Color: Deep black, opaque; Luster: Vitreous to sub-metallic; Crystal structure: Trigonal/Hexagonal; Cleavage: Indistinct; Specific Gravity: 3.0-3.2

Formation & geological history

Forms in igneous and metamorphic rocks, most commonly in granitic pegmatites where hydrothermal fluids rich in boron crystallize over millions of years.

Uses & applications

Used primarily in jewelry as a tumbled stone or cabochon, as a metaphysical protection stone, and industrially for its pyroelectric and piezoelectric properties.

Geological facts

Black tourmaline, also known as Schorl, is the most common variety of tourmaline, accounting for approximately 95% of all tourmaline found in nature. It can generate an electrical charge when heated or squeezed.

Field identification & locations

Identify by its deep black color, lack of transparency even under bright light, and often long, columnar striated crystals when in raw form. Commonly found in Brazil, Namibia, and the USA.