Rock Identifier
Black Tourmaline (Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)) — mineral
mineral

Black Tourmaline

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

Hardness: 7-7.5 (Mohs scale); Color: Jet black, opaque; Luster: Vitreous to sub-metallic; Crystal Structure: Trigonal/Hexagonal with vertical striations; Cleavage: Indistinct; Specific Gravity: 3.0-3.25

Hardness
7-7
Color
Jet black, opaque
Luster
Vitreous to sub-metallic
Identified More mineral

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Physical properties

Hardness: 7-7.5 (Mohs scale); Color: Jet black, opaque; Luster: Vitreous to sub-metallic; Crystal Structure: Trigonal/Hexagonal with vertical striations; Cleavage: Indistinct; Specific Gravity: 3.0-3.25

Formation & geological history

Formed primarily in pegmatites through hydrothermal and magmatic processes; can also occur in metamorphic rocks مثل schists. It is rich in boron and iron, allowing it to crystallize in late-stage igneous environments.

Uses & applications

Used in the gemstone industry for beads and carvings, as a source of boron, and in scientific instruments for its pyroelectric and piezoelectric properties. Highly valued as a protective stone in the metaphysical community.

Geological facts

One of the most common varieties of tourmaline, Schorl makes up about 95% of all tourmaline found in nature. It is naturally pyroelectric, meaning it can generate an electrical charge when heated.

Field identification & locations

Identify by its characteristic vertical striations along the prism faces, rounded triangular cross-section, and deep black opacity. Commonly found in Brazil, Namibia, Pakistan, and the United States (Maine and California).