mineral

Black Tourmaline (Schorl) on Quartz

NaFe2+3Al6(Si6O18)(BO3)3(OH)3(OH)

AI-generated identification · may be incorrect

Hardness: 7-7.5 (Mohs scale), Color: Inky black, Luster: Vitreous to resinous, Crystal Structure: Trigonal, Cleavage: Indistinct, Specific Gravity: 3.0-3.2

Hardness: 7-7

Identified July 8, 2026More mineral →

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Physical properties

Hardness: 7-7.5 (Mohs scale), Color: Inky black, Luster: Vitreous to resinous, Crystal Structure: Trigonal, Cleavage: Indistinct, Specific Gravity: 3.0-3.2

Formation & geological history

Formed in igneous pegmatites or metamorphic rocks through hydrothermal processes where boron-rich fluids are present. Often found associated with quartz, feldspar, and mica.

Uses & applications

Primarily used for mineral specimen collecting, metaphysical jewelry, and industrial applications such as pressure gauges due to its piezoelectric properties.

Geological facts

Schorl is the most common member of the tourmaline group, making up 95% of all tourmaline in nature. It is strongly pyroelectric, meaning it develops an electrical charge when heated.

Field identification & locations

Identify by its characteristic trigonal cross-section (often rounded triangular), vertical striations on crystal faces, and intense black color. Found worldwide, with major deposits in Brazil and Namibia.