mineral

Black Tourmaline (Schorl)

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

Hardness: 7-7.5. Color: Inky black. Luster: Vitreous to sub-metallic. Crystal system: Trigonal/Hexagonal. Cleavage: Indistinct. Specific Gravity: 3.0-3.25. Typically forms elongated prismatic crystals with vertical striations.

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

Identified July 2, 2026More mineral →

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Physical properties

Formation & geological history

Forms primarily in granitic pegmatites and metamorphic rocks like schists during hydrothermal processes. Most common species in the tourmaline group, appearing in high-temperature environments.

Uses & applications

Extensively used for protection jewelry, metaphysical practices, and mineral collection. Industrially, it has been used in pressure gauges due to its piezoelectric and pyroelectric properties.

Geological facts

Schorl is known for its ability to become electrically charged when heated (pyroelectricity) or rubbed (piezoelectricity). It is by far the most abundant member of the complex tourmaline mineral group.

Field identification & locations

Identify by its deep black color, vertical striations on crystal faces, and a rounded triangular cross-section. Commonly found in Brazil, Namibia, and the United States (Maine/California).

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Gypsum (variety Selenite or Alabaster)

Calcium sulfate dihydrate (CaSO4·2H2O)

Mineral

Nephrite Jade

Nephrite

Mineral/Rock

Granite

Granite (Phaneritic intrusive igneous rock)

igneous