mineral
Green Tourmaline (Verdelite)
Na(Li,Al)3Al6(BO3)3Si6O18(OH)4 (Elbaite)
Hardness: 7-7.5 on Mohs scale; Color: Olive to lime green; Luster: Vitreous; Crystal Structure: Trigonal/Hexagonal with distinct vertical striations; Cleavage: Indistinct; Specific Gravity: 3.06.
- Hardness
- 7-7
- Color
- Olive to lime green
- Luster
- Vitreous
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Physical properties
Hardness: 7-7.5 on Mohs scale; Color: Olive to lime green; Luster: Vitreous; Crystal Structure: Trigonal/Hexagonal with distinct vertical striations; Cleavage: Indistinct; Specific Gravity: 3.06.
Formation & geological history
Formed in granitic pegmatites through hydrothermal processes. The green color is typically caused by the presence of iron or chromium. Found in geologic environments ranging from millions to billions of years old.
Uses & applications
Primarily used as a gemstone in jewelry, as mineral specimens for collectors, and also used in pressure gauges due to its piezoelectric properties.
Geological facts
Tourmaline is unique because it is both pyroelectric (generates electricity when heated) and piezoelectric (generates electricity under pressure). The name 'Verdelite' comes from the Latin 'viridis' meaning green.
Field identification & locations
Identified in the field by its characteristic elongated prismatic crystals with vertical striations and triangular cross-sections. Commonly found in Brazil, Namibia, Afghanistan, and the USA (Maine and California).
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