mineral

Black tourmaline (schorl) in a light-colored host rock

Schorl, NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄; host appears to be feldspar-rich pegmatite

AI-generated identification · may be incorrect

Black, vitreous to submetallic, commonly striated prismatic crystals; Mohs hardness 7–7.5, trigonal crystal system, poor cleavage and uneven fracture. The pale host is too indistinct in the image to identify confidently.

Identified October 14, 2026More mineral →

Explore Black tourmaline (schorl) in a light-colored host rock in the encyclopedia →

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Physical properties

Formation & geological history

Tourmaline commonly crystallizes in boron-rich granitic pegmatites as magma cools; such bodies may form during episodes of continental crustal melting, across a wide range of geological ages.

Uses & applications

Tourmaline is collected as a mineral specimen and, when transparent and well formed, cut for jewelry; pegmatite minerals including feldspar also have industrial uses.

Geological facts

Schorl is the most common tourmaline species and is strongly piezoelectric: mechanical pressure can produce an electrical charge.

Field identification & locations

Look for black, hard, elongated crystals with lengthwise grooves, often embedded in coarse pale pegmatite. The image is consistent with this association, but crystal shape and host are not clear enough for a definitive identification.