mineral

Black Tourmaline (Schorl)

NaFe3+3Al6(BO3)3Si6O18(OH)4

AI-generated identification · may be incorrect

Hardness: 7-7.5 Mohs. Color: Deep black. Luster: Vitreous to resinous. Crystal structure: Trigonal (often striated prismatic crystals or rough nodular aggregates). Cleavage: Indistinct. Specific gravity: 3.0-3.2.

Hardness: 7-7
Color: Deep black
Luster: Vitreous to resinous

Identified July 27, 2026More mineral →

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Physical properties

Formation & geological history

Forms primarily in pegmatites, high-grade metamorphic rocks, and hydrothermal veins during the late stages of magmatic crystallization.

Uses & applications

Popularly used for metaphysical and grounding purposes, lapidary carvings, mineral collection specimens, and historically in scientific instruments due to its pyroelectric properties.

Geological facts

Black tourmaline, known as schorl, is the most common variety of tourmaline, accounting for nearly 95% of all tourmaline found in nature. It exhibits strong piezoelectricity and pyroelectricity, generating an electrical charge under heat or pressure.

Field identification & locations

Identified by its intense black color, high hardness (scratches glass), triangular or rounded-triangular cross-section, and characteristic parallel striations along crystal faces. Commonly found in pegmatite fields worldwide, such as in Brazil, Madagascar, and Maine, USA.