mineral

Black tourmaline in quartz

Schorl tourmaline (NaFe3Al6(BO3)3Si6O18(OH)4) with quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: tourmaline 7–7.5, quartz 7 Mohs; black tourmaline is vitreous and commonly striated, while quartz is translucent, glassy, and often milky or gray. The specimen shows prismatic black schorl embedded in massive to crystalline quartz.

Hardness: tourmaline 7–7

Identified September 16, 2026More mineral →

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Physical properties

Formation & geological history

Forms in boron-rich granitic pegmatites and hydrothermal veins as magma cools and volatile-rich fluids crystallize. Most examples are Precambrian to Phanerozoic, depending on locality.

Uses & applications

Used as a collector specimen; gem-quality schorl is uncommon in jewelry, while quartz is widely used in abrasives, glass, electronics, and ornamental objects.

Geological facts

Schorl is the most common tourmaline species and is strongly piezoelectric and pyroelectric. Quartz and tourmaline commonly grow together in pegmatites, producing contrasting black-and-white specimens.

Field identification & locations

Identify it by the black, longitudinally striated prismatic crystals and hardness near quartz; a glass-scratch test is useful, but avoid damaging the specimen. Common sources include Brazil, Afghanistan, Pakistan, Madagascar, Namibia, and the United States.