mineral

Black Tourmaline (Schorl)

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

Hardness: 7 to 7.5 on Mohs scale; Color: Jet black; Luster: Vitreous to sub-metallic; Crystal Structure: Trigonal (often hexagonal prisms with vertical striations); Cleavage: Indistinct; Specific Gravity: 3.0 to 3.25.

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

Identified July 16, 2026More mineral →

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Physical properties

Formation & geological history

Formed primarily in pegmatites through hydrothermal processes where boron-rich fluids interact with granite intrusion environments. It can also be found in metamorphic rocks like schist.

Uses & applications

Extensively used in crystal healing for grounding and protection, as a collector's mineral, and historically for its pyroelectric and piezoelectric properties in scientific instruments.

Geological facts

It is pyroelectric, meaning it generates an electrical charge when heated. It also contains complex borosilicates and is the most common member of the tourmaline group.

Field identification & locations

Identify in the field by its deep black color, vertical striations along the length of the crystal, and a characteristic rounded triangular cross-section. Commonly found in Brazil, Namibia, and the USA (notably California and Maine).

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Sandstone with Mineral Veining or Crust

Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)

sedimentary

Schist

Metamorphic

Potassium Feldspar (Orthoclase)

Orthoclase (KAlSi3O8)

mineral

Gypsum (variety Selenite or Alabaster)

Calcium sulfate dihydrate (CaSO4·2H2O)

Mineral

Nephrite Jade

Nephrite

Mineral/Rock