mineral
Tourmaline
Complex boron silicate, (Na,Ca)(Al,Fe,Li)_3Al_6(BO_3)_3Si_6O_18(OH)_4
AI-generated identification · may be incorrectMohs hardness of 7-7.5, black or dark brown color, vitreous luster, trigonal crystal system with striated prismatic crystals.
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Physical properties
Mohs hardness of 7-7.5, black or dark brown color, vitreous luster, trigonal crystal system with striated prismatic crystals.
Formation & geological history
Forms in pegmatites and hydrothermal veins during late-stage crystallization of magma.
Uses & applications
Used in jewelry, scientific pressure sensors, and as collector specimens.
Geological facts
Tourmaline exhibits strong pyroelectric and piezoelectric properties, generating an electrical charge when heated or compressed.
Field identification & locations
Identify by its distinct triangular cross-section, vertical striations along the prism face, and lack of cleavage. Commonly found worldwide in granitic pegmatites.
