mineral
Black Tourmaline (Schorl)
Schorl (Sodium iron aluminum borosilicate hydroxide) NaFe3Al6(BO3)3Si6O18(OH)4
Hardness: 7-7.5 (Mohs), Color: Inky black, Luster: Vitreous to sub-resinous, Crystal Structure: Trigonal/Hexagonal, Specific Gravity: 3.1-3.2
- Hardness
- 7-7
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Physical properties
Hardness: 7-7.5 (Mohs), Color: Inky black, Luster: Vitreous to sub-resinous, Crystal Structure: Trigonal/Hexagonal, Specific Gravity: 3.1-3.2
Formation & geological history
Typically found in granitic pegmatites, high-temperature hydrothermal veins, and metamorphic rocks such as schists and marbles. It forms through late-stage crystallization of cooling magma.
Uses & applications
Mainly used as a gemstone, in jewelry, and highly popular for metaphysical/collecting purposes. Due to its piezoelectric properties, it has historical use in pressure gauges.
Geological facts
Black tourmaline is both piezoelectric (generates electricity under pressure) and pyroelectric (generates electricity when heated), which allows it to attract light particles like dust.
Field identification & locations
Identify by its deep black color, vertical striations (if raw), and hardness. It is commonly found in Brazil, Africa, and parts of the United States like Maine and California.
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Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Schist
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