Black Tourmaline
Schorl · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal, typically forming prismatic crystals with striations
Mineral Group
Silicates, specifically Cyclosilicates
Chemical Formula
NaFe2+3Al6(Si6O18)(BO3)3(OH)4
Formation Process
Pegmatitic and hydrothermal veins associated with granitic magmas
About This Crystal
Tumbled, polished stone showing deep jet-black color, opaque transparency, and a vitreous to sub-metallic luster on its smoothed surface.
Physical Characteristics
Color is black; streak is white; conchoidal to uneven fracture; cleavage is indistinct; specific gravity is approximately 3.0-3.2; brittle tenacity; non-magnetic.
Optical Properties
Uniaxial negative with strong pleochroism in rough crystal form; singly or doubly refractive depending on viewing angle, but opaque in this tumbled form.
Hardness & Durability
Origin Region
Brazil, Pakistan, Madagascar, USA, and worldwide in pegmatites
Hardness & Durability
Mohs hardness of 7 to 7.5; good durability, though it can have micro-fractures making it sensitive to hard impacts.
Care & Maintenance
Clean with warm soapy water and a soft cloth; avoid harsh chemicals, ultrasonic cleaners, and prolonged direct sunlight.
Rarity & Value
Common; widely available and affordable, usually sold as tumbled stones, raw specimens, or simple jewelry.
Special Characteristics
Known for pyroelectric and piezoelectric properties, generating an electrical charge when heated or subjected to pressure.
Lore & History
Historically used as a protective talisman against negative energies and psychic attack; strongly associated with the Root Chakra in modern crystal healing.