mineral

Black tourmaline beads (likely schorl)

Schorl, NaFe²⁺₃Al₆(BO₃)₃Si₆O₁₈(OH)₄

AI-generated identification · may be incorrect

Opaque black, vitreous to subvitreous luster; trigonal crystal structure, commonly prismatic with strong longitudinal striations. Mohs hardness 7–7.5; specific gravity about 3.0–3.3. The pictured material is polished and drilled into beads.

Identified August 16, 2026More mineral →

Explore Black tourmaline beads (likely schorl) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Forms mainly in boron-rich granitic pegmatites and hydrothermal veins during late-stage crystallization, commonly in Precambrian to younger terrains. Individual crystals may be millions to billions of years old, depending on the host rock.

Uses & applications

Used for jewelry, ornamental beads, mineral collecting, and sometimes claimed—without strong scientific support—as an electromagnetic-protection stone. Polished schorl is durable for necklaces and bracelets.

Geological facts

Schorl is the most common tourmaline species and is strongly piezoelectric and pyroelectric, developing electrical charge when heated or pressured.

Field identification & locations

Identify by black color, high hardness, dense feel, and possible lengthwise striations; beads may be confused with obsidian, hematite, or black glass. Common sources include Brazil, Afghanistan, Pakistan, Madagascar, Namibia, and the United States.