igneous
Black Tourmaline in Quartz
Schorl (NaFe3Al6(BO3)3Si6O18(OH)4) in Silicon Dioxide (SiO2)
Hardness: 7 (Quartz) to 7.5 (Tourmaline); Color: White/creamy matrix with black prismatic inclusions; Luster: Vitreous; Crystal Structure: Trigonal (Tourmaline) and Hexagonal (Quartz); Cleavage: None/Indistinct; Specific Gravity: 2.65 - 3.1.
- Hardness
- 7 (Quartz) to 7
- Color
- White/creamy matrix with black prismatic inclusions
- Luster
- Vitreous
Identified More igneous →
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Physical properties
Hardness: 7 (Quartz) to 7.5 (Tourmaline); Color: White/creamy matrix with black prismatic inclusions; Luster: Vitreous; Crystal Structure: Trigonal (Tourmaline) and Hexagonal (Quartz); Cleavage: None/Indistinct; Specific Gravity: 2.65 - 3.1.
Formation & geological history
Formed in granitic pegmatites through hydrothermal processes. As the molten rock cools, high-pressure fluids allow for the growth of these distinct, needle-like black tourmaline crystals within the quartz matrix.
Uses & applications
Primarily used as a pocket stone for metaphysical properties (protection/grounding), as an ornamental decorative stone, or as a collector mineral specimen.
Geological facts
Black tourmaline is known as Schorl and is naturally pyroelectric, meaning it can generate an electric charge when heated or squeezed (piezoelectric). It was once used by the Dutch to pull ash out of clay pipes.
Field identification & locations
Identify in the field by the distinct elongated, columnar black crystals with vertical striations embedded in a white or translucent quartz rock. Commonly found in Brazil, Namibia, and the United States (Maine/California).
