mineral

Black tourmaline (schorl) in a light-colored pegmatite matrix

Schorl, NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄

AI-generated identification · may be incorrect

The dark, lustrous material appears roughly prismatic and striated, consistent with schorl; hardness 7–7.5 Mohs, trigonal crystal system, and poor cleavage. The pale host may be quartz or feldspar; composition cannot be confirmed from the image alone.

Identified October 14, 2026More mineral →

Explore Black tourmaline (schorl) in a light-colored pegmatite matrix in the encyclopedia →

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Physical properties

Formation & geological history

Tourmaline commonly crystallizes in boron-rich granitic pegmatites as magma cools and concentrates volatile elements. Such deposits form in many geological periods, often alongside quartz and feldspar.

Uses & applications

Attractive crystals are collected and occasionally cut as gemstones; schorl is also used decoratively, while tourmaline has limited specialty electrical applications.

Geological facts

Schorl is the most common tourmaline variety and is typically black due to iron. Its crystals often show strong lengthwise grooves.

Field identification & locations

Look for opaque black, elongated crystals with pronounced longitudinal striations in a coarse quartz–feldspar matrix. Common in pegmatites worldwide, including Brazil, Afghanistan, and the United States.