Black Tourmaline
Schorl · Semi-Precious Gemstone and Mineral Specimen
Crystal System
Trigonal, typically occurring in prismatic crystals with striated faces
Mineral Group
Silicates, specifically Cyclosilicates
Chemical Formula
NaFe3+2Al6(Si6O18)(BO3)3(OH)4
Formation Process
Pegmatitic and hydrothermal, forming in igneous and metamorphic rocks under high-temperature and high-pressure conditions
About This Crystal
Opaque, jet-black faceted gemstone cut into a heart shape, set in an ornate silver ring, showing a vitreous to sub-metallic luster on its polished facets
Physical Characteristics
Black body color, colorless streak, conchoidal to uneven fracture, no distinct cleavage, specific gravity of approximately 3.0 to 3.2, brittle tenacity
Optical Properties
Uniaxial negative with strong pleochroism, doubly refractive, and completely opaque in thicker sections
Hardness & Durability
Origin Region
Brazil, Pakistan, Madagascar, USA (California, Maine), and Russia; found in pegmatites and hydrothermal veins
Hardness & Durability
Mohs hardness of 7 to 7.5, fair toughness, good durability for everyday jewelry wear although vulnerable to sharp impacts
Care & Maintenance
Clean with warm soapy water and a soft brush, avoid harsh chemical cleaners and ultrasonic cleaning systems
Rarity & Value
Common, widely available, with value heavily dependent on the quality of the cut, polish, and the setting rather than the raw stone
Special Characteristics
Strong pyroelectric and piezoelectric properties, generating an electric charge when heated or subjected to mechanical pressure
Lore & History
Historically used as a protective talisman against negative energies, frequently associated with the Root Chakra in modern crystal healing practices