mineral
Tourmaline crystal
Tourmaline Group (Complex Borosilicate)
AI-generated identification · may be incorrectHardness of 7-7.5 on Mohs scale, typically prismatic crystals with vertical striations, vitreous to subresinous luster, specific gravity 3.0-3.2, no true cleavage.
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Physical properties
Hardness of 7-7.5 on Mohs scale, typically prismatic crystals with vertical striations, vitreous to subresinous luster, specific gravity 3.0-3.2, no true cleavage.
Formation & geological history
Forms in pegmatites and hydrothermal veins associated with granitic magmas, as well as in metamorphic rocks like schists and marbles.
Uses & applications
Used as gemstones in jewelry, in pressure-sensing equipment due to piezoelectric properties, and highly sought after by mineral collectors.
Geological facts
Tourmaline displays a wide variety of colors and can exhibit pleochroism, where the color changes depending on the viewing angle.
Field identification & locations
Easily identified by its characteristic triangular cross-section and distinct parallel striations along the length of the crystal prism.
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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
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