mineral

Black Tourmaline

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

Hardness: 7-7.5 Mohs scale. Color: Opaque black. Luster: Vitreous to sub-metallic. Crystal structure: Trigonal/Hexagonal with vertical striations. Cleavage: Indistinct. Specific gravity: 3.0-3.2.

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

Identified June 11, 2026More mineral →

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Physical properties

Hardness: 7-7.5 Mohs scale. Color: Opaque black. Luster: Vitreous to sub-metallic. Crystal structure: Trigonal/Hexagonal with vertical striations. Cleavage: Indistinct. Specific gravity: 3.0-3.2.

Formation & geological history

Formed in igneous and metamorphic rocks, most commonly in pegmatites through hydrothermal processes. Found in ancient geological formations worldwide.

Uses & applications

Used in industrial capacitors and sensors due to its piezoelectric properties; also popular in jewelry, as cabochons, and as a 'talisman' in metaphysical collecting.

Geological facts

Black tourmaline is pyroelectric, meaning it generates an electrical charge when heated. It is the most common variety of the tourmaline group, making up 95% of all tourmaline found in nature.

Field identification & locations

Identify by long, columnar crystals with vertical striations (lines) along the sides and a triangular cross-section. Commonly found in Brazil, Africa, and the United States.