mineral

Schorl (Black Tourmaline)

Sodium Iron Aluminum Borosilicate (NaFe3Al6(BO3)3Si6O18(OH)4)

Hardness: 7-7.5 on Mohs scale; Color: Jet black, opaque; Luster: Vitreous to sub-metallic; Crystal Structure: Trigonal (striated prismatic columns); Cleavage: Indistinct; Specific Gravity: 3.0-3.2

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

Identified March 15, 2026More mineral →

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Physical properties

Hardness: 7-7.5 on Mohs scale; Color: Jet black, opaque; Luster: Vitreous to sub-metallic; Crystal Structure: Trigonal (striated prismatic columns); Cleavage: Indistinct; Specific Gravity: 3.0-3.2

Formation & geological history

Formed primarily in pegmatites through hydrothermal processes and late-stage magmatic cooling. It can also occur in metamorphic rocks مثل schists or as detrital grains in sedimentary deposits. Specimens can range from Precambrian to recent ages.

Uses & applications

Extensively used for metaphysical jewelry and protection stones, industrial applications for its piezoelectric and pyroelectric properties (pressure and temperature sensors), and as a minor ore of boron.

Geological facts

Schorl makes up about 95% of all tourmaline found in nature. It is famous for its 'piezoelectric' effect, meaning it can generate an electrical charge when mechanically stressed or heated.

Field identification & locations

Identify in the field by its distinct vertical striations on elongated crystal faces, triangular cross-section, and jet-black opaque color. It is commonly found in Brazil, Namibia, the USA (Maine/California), and Pakistan.

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