mineral
Tourmaline
Schorl (Sodium Iron Aluminum Boron Silicate Hydroxide)
AI-generated identification · may be incorrectHardness of 7-7.5 on the Mohs scale, typically black to dark brown, vitreous luster, trigonal crystal system with prominent vertical striations, and indistinct cleavage.
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Physical properties
Hardness of 7-7.5 on the Mohs scale, typically black to dark brown, vitreous luster, trigonal crystal system with prominent vertical striations, and indistinct cleavage.
Formation & geological history
Forms primarily in pegmatites, granites, and metamorphic rocks through hydrothermal processes and fractional crystallization of magmas.
Uses & applications
Used in mineral specimens for collectors, piezoelectric and pyroelectric applications in electronics, and occasionally cut into gemstones.
Geological facts
Tourmaline has one of the widest color ranges of any mineral group due to complex trace element substitutions in its crystal lattice.
Field identification & locations
Easily identified in the field by its characteristic three-sided or rounded triangular cross-section and deep parallel striations along the prism length.
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Other mineral specimens
Gneiss or Schist
Gneiss or Mica Schist with Garnet
Metamorphic
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Tumbled granite
Granite, a coarse-grained felsic intrusive igneous rock
igneous
Pegmatite with Tourmaline and Quartz
Igneous Pegmatite
igneous
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Granite
Granite (Phaneritic intrusive igneous rock)
igneous