mineral
Black Tourmaline (Schorl)
NaFe3+3Al6(BO3)3Si6O18(OH)4
AI-generated identification · may be incorrectHardness 7.0-7.5 on Mohs scale, deep black color, vitreous to resinous luster, trigonal/prismatic crystal structure with distinct vertical striations, uneven to conchoidal fracture.
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Physical properties
Hardness 7.0-7.5 on Mohs scale, deep black color, vitreous to resinous luster, trigonal/prismatic crystal structure with distinct vertical striations, uneven to conchoidal fracture.
Formation & geological history
Formed in igneous pegmatites, metamorphic rocks, and hydrothermally altered granites through boron-bearing fluid activity during late-stage crystallization.
Uses & applications
Popular for lapidary work, specimen collections, metaphysical usage as a protective stone, and historical scientific experiments involving its pyroelectric and piezoelectric properties.
Geological facts
Black tourmaline, also known as Schorl, accounts for nearly 95% of all natural tourmaline on Earth. When heated or rubbed, it develops an electric charge that attracts light particles like dust.
Field identification & locations
Identify in the field by its dark black color, high hardness, parallel striations along elongated prismatic crystals, and triangular cross-section. Widely found in Brazil, Madagascar, Pakistan, and the USA.
More like this
Other mineral specimens
Gneiss or Schist
Gneiss or Mica Schist with Garnet
Metamorphic
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Pegmatite with Tourmaline and Quartz
Igneous Pegmatite
igneous
Granite
Granite (Phaneritic intrusive igneous rock)
igneous
Septarian Pebble
Septarian nodule / Concretion
sedimentary