Green Tourmaline
Elbaite · Semi-Precious Gemstone and Mineral Specimen
Crystal System
Trigonal, typically forming prismatic crystals with rounded triangular cross-sections.
Mineral Group
Silicates (Cyclosilicates)
Chemical Formula
Na(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)4
Formation Process
Pegmatitic and hydrothermal formation, typically crystallizing from lithium- and boron-rich magmatic fluids at high temperatures and pressures.
About This Crystal
The specimen exhibits a vibrant yellowish-green to olive-green color, with a translucent to transparent appearance and a vitreous luster. It shows typical tumbled or partially water-worn characteristics with smooth curved surfaces and internal fibrous inclusions.
Physical Characteristics
Body color ranges from olive green to yellowish-green; streak is white; distinct cleavage is absent, breaking with an uneven to conchoidal fracture; specific gravity is approximately 3.01 to 3.10; brittle tenacity.
Optical Properties
Doubly refractive with uniaxial negative optical character; exhibits noticeable dichroism with varying shades of green depending on the viewing angle; refractive index ranges from 1.620 to 1.650.
Hardness & Durability
Origin Region
Brazil, Madagascar, Afghanistan, Nigeria, and the United States (California, Maine). Found in pegmatites and hydrothermal veins.
Hardness & Durability
Mohs hardness of 7 to 7.5, offering good durability and making it suitable for most types of jewelry, though care should be taken with sudden thermal shocks.
Care & Maintenance
Clean with warm soapy water and a soft brush; avoid ultrasonic and steam cleaners due to internal fractures and inclusions; store separately from harder gems like diamond or corundum.
Rarity & Value
Uncommon to rare depending on clarity and color saturation; vivid emerald greens command higher prices, while olive or yellowish-green varieties are more accessible; heat treatment is occasionally used to improve color.
Special Characteristics
Strong pyroelectric and piezoelectric properties, meaning it can generate an electrical charge when heated or subjected to mechanical pressure.
Lore & History
Historically used as an amulet for protection and healing. In modern crystal lore, green tourmaline is associated with the heart chakra, vitality, and emotional growth, though these are traditional beliefs rather than scientific claims.