mineral

Black Tourmaline (Schorl)

NaFe2+3Al6(BO3)3Si6O18(OH)4

Hardness 7.0-7.5 on Mohs scale. Opaque jet black color with a vitreous to resinous luster. Trigonal crystal system featuring distinctive vertical striations along elongated prismatic crystals. Indistinct cleavage, subconchoidal to uneven fracture, specific gravity around 3.0-3.3.

Identified July 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed through magmatic and hydrothermal processes, predominantly found in granitic pegmatites, metamorphic rocks like schists, and hydrothermal veins. Dates from Precambrian to Cenozoic geological eras.

Uses & applications

Widely collected as crystal specimens, used in jewelry, lapidary carvings, and metaphysical applications. Industrially utilized historically for its pyroelectric and piezoelectric properties in pressure gauges.

Geological facts

Schorl is the most common variety of tourmaline, accounting for roughly 95% of all natural tourmaline found on Earth. It becomes electrically charged when heated (pyroelectricity) or under mechanical pressure (piezoelectricity).

Field identification & locations

Identified in the field by its deep black color, high hardness, triangular/rounded cross-section, and vertical striations along the length of the crystal. Commonly found in pegmatite districts worldwide including Brazil, Madagascar, California, and Pakistan.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Sandstone with Mineral Veining or Crust

Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)

sedimentary

Potassium Feldspar (Orthoclase)

Orthoclase (KAlSi3O8)

mineral

Gypsum (variety Selenite or Alabaster)

Calcium sulfate dihydrate (CaSO4·2H2O)

Mineral

Nephrite Jade

Nephrite

Mineral/Rock