mineral
Black Tourmaline
Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)
AI-generated identification · may be incorrectHardness: 7-7.5. Color: Black. Luster: Vitreous to sub-metallic. Crystal structure: Trigonal/hexagonal prisms with vertical striations. Cleavage: Indistinct. Specific gravity: 3.0-3.2.
- Hardness
- 7-7
- Color
- Black
- Luster
- Vitreous to sub-metallic
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Physical properties
Hardness: 7-7.5. Color: Black. Luster: Vitreous to sub-metallic. Crystal structure: Trigonal/hexagonal prisms with vertical striations. Cleavage: Indistinct. Specific gravity: 3.0-3.2.
Formation & geological history
Forms in igneous and metamorphic rocks, most notably in pegmatites through hydrothermal activity. It can be found in formations dating back millions of years depending on the host rock.
Uses & applications
Primarily used in jewelry, as raw specimens for metaphysical collection, and historically in various scientific instruments due to its piezoelectric properties.
Geological facts
Tourmaline is pyroelectric, meaning it generates an electrical charge when heated. Large, well-formed crystals are highly prized by mineral collectors.
Field identification & locations
Identify in the field by its distinct vertical striations along the length of the crystal and its characteristic triangular cross-section. Commonly found in Brazil, Namibia, and the USA (California and Maine).
