mineral

Black Tourmaline (Schorl)

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

Hardness: 7-7.5 on Mohs scale. Color: Jet black to brownish-black. Luster: Vitreous to sub-metallic. Crystal system: Trigonal. Cleavage: Indistinct. Specific gravity: 3.0-3.2. These specimens are tumbled and polished.

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

Identified July 7, 2026More mineral →

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Physical properties

Formation & geological history

Forms primarily in granitic pegmatites, hydrothermal veins, and metamorphic rocks like schist and gneiss. It is a boron-rich silicate mineral commonly associated with quartz and feldspar.

Uses & applications

Used extensively in jewelry, as protective talismans in metaphysical circles, and historically in scientific instruments due to its piezoelectric and pyroelectric properties.

Geological facts

Black tourmaline is the most common member of the tourmaline group, making up about 95% of all tourmaline found in nature. It was known as 'Schorl' as early as the 14th century, named after a village in Saxony, Germany.

Field identification & locations

Identified by its deep black color, vertical striations (if untumbled), and strong hardness. It is common in pegmatites globally, with notable deposits in Brazil, Namibia, and China. Collectors look for high-gloss polish and minimal inclusions.

Other mineral specimens

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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