mineral

Black Tourmaline (Schorl)

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

Hardness: 7-7.5 Mohs scale. Color: Deep black, opaque. Luster: Vitreous to resinous. Crystal Structure: Trigonal, often forming vertically striated prismatic crystals. Cleavage: Indistinct. Specific Gravity: 3.0-3.25.

Hardness: 7-7
Color: Deep black, opaque
Luster: Vitreous to resinous

Identified July 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed primarily in pegmatites, granites, and high-grade metamorphic rocks during igneous activity and hydrothermal fluids rich in boron.

Uses & applications

Used widely in metaphysical jewelry, crystal healing collections, as a mineral specimen, and historically in scientific instruments like pressure gauges due to its piezoelectric properties.

Geological facts

Black Tourmaline, or Schorl, accounts for nearly 95% of all tourmaline found in nature. It exhibits both pyroelectricity (generates electric charge when heated) and piezoelectricity (generates electric charge under mechanical stress).

Field identification & locations

Identified by its intense black color, high hardness, distinctive vertical striations, and lack of good cleavage. Commonly found in Brazil, Madagascar, USA (California and Maine), Pakistan, and Namibia.

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