mineral

Black tourmaline in quartz (probable)

Quartz (SiO₂) with schorl tourmaline, NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄

AI-generated identification · may be incorrect

Translucent gray-to-honey quartz enclosing black, opaque tourmaline aggregates; quartz hardness 7 and tourmaline 7–7.5 Mohs, with vitreous luster and no obvious cleavage. Tourmaline commonly forms prismatic crystals with strong longitudinal striations, though the crystals here appear massive or broken.

Identified September 16, 2026More mineral →

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Physical properties

Formation & geological history

A hydrothermal pegmatite specimen formed when silica-rich fluids crystallized quartz and boron-rich fluids formed schorl, typically during late stages of granitic intrusion. Such pegmatites are generally Precambrian to Phanerozoic in age.

Uses & applications

Collected as a natural mineral specimen; attractive pieces may be used decoratively, while gem-quality quartz or tourmaline can be cut, though this example appears unsuitable for jewelry.

Geological facts

Black schorl is the most common tourmaline variety and often occurs dramatically embedded in clear or smoky quartz. Tourmaline is piezoelectric and can develop electrical charge when heated or compressed.

Field identification & locations

Identify by translucent quartz surrounding black, hard, vitreous tourmaline; a steel scratch test should not easily mark either mineral. Common sources include Brazil, Afghanistan, Pakistan, Madagascar, and the United States, especially Maine and California.