mineral

Black Tourmaline in Quartz Matrix

Schorl (NaFe3Al6(BO3)3Si6O18(OH)4) with Quartz (SiO2)

Hardness: 7-7.5 (Schorl) / 7 (Quartz); Color: Opaque jet black needles in white or translucent grey-white matrix; Luster: Vitreous to sub-metallic; Crystal structure: Trigonal (hexagonal prisms); Cleavage: Indistinct; Specific Gravity: Approx 3.0-3.2 (Schorl).

Hardness: 7-7
Luster: Vitreous to sub-metallic

Identified February 14, 2026More mineral →

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Physical properties

Formation & geological history

Formed in granitic pegmatites during the late-stage crystallization of magma where hot, boron-rich fluids are present. These specimens can range in age from millions to billions of years depending on the specific pegmatite belt.

Uses & applications

Used primarily for mineral specimen collecting and metaphysical purposes. Industrial black tourmaline is used in electrical pressure gauges and for its pyroelectric/piezoelectric properties.

Geological facts

Black tourmaline (Schorl) is the most common member of the tourmaline family. The French label in the photo 'quartz titane brut' suggests it might have been misidentified as titanium-bearing (rutile) quartz, but the blocky, striated habit is diagnostic of Schorl tourmaline.

Field identification & locations

Identify in the field by the long, needle-like or columnar black crystals with vertical striations, often embedded in white milky quartz. Commonly found in Brazil, Pakistan, and the United States (Maine/California).

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