mineral

Black tourmaline bead bracelet

Schorl tourmaline, NaFe²⁺₃Al₆(BO₃)₃Si₆O₁₈(OH)₄

AI-generated identification · may be incorrect

Polished, nearly black to brown translucent beads with vitreous luster; Mohs hardness 7–7.5, trigonal crystal structure, and indistinct cleavage. The visible brown-gold areas may reflect dravite-rich zoning or surface inclusions.

Identified August 19, 2026More mineral →

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Physical properties

Formation & geological history

Tourmaline crystallizes in boron-rich hydrothermal veins, pegmatites, and metamorphic rocks, commonly during Paleozoic–Mesozoic mountain-building events. Major sources include Brazil, Afghanistan, Pakistan, Madagascar, Namibia, and the United States.

Uses & applications

Used as a gemstone, ornamental bead material, and collector mineral; occasionally marketed for purported metaphysical or electrical properties, which lack scientific support. It is not generally used as a construction stone.

Geological facts

Tourmaline is strongly pleochroic and becomes electrically polarized when heated or compressed (pyroelectric and piezoelectric). Schorl is the most common tourmaline species.

Field identification & locations

Identify by its black color, glassy luster, hardness, lack of obvious cleavage, and—on crystal specimens—characteristic striated prismatic form. A bracelet’s beads may be treated or assembled from mixed-quality material, so definitive identification requires testing or laboratory analysis.