Black Tourmaline
Schorl (Tourmaline Group) · Mineral Specimen and Semi-Precious Gemstone
Crystal System
Trigonal, typically forming prismatic crystals with striated faces
Mineral Group
Silicates, Cyclosilicates
Chemical Formula
NaFe3+2Al6(Si6O18)(BO3)3(OH)4
Formation Process
Primarily forms in pegmatites, hydrothermal veins, and metamorphic rocks under high temperature and pressure conditions
About This Crystal
The specimen is intricately carved into the shape of a small turtle, displaying a deep, opaque black body color with a high-polish metallic to sub-vitreous luster that reflects light brightly on the carved shell ridges.
Physical Characteristics
Color is solid black with a brownish-black to black streak. It exhibits no true cleavage, a conchoidal to uneven fracture, brittle tenacity, a specific gravity of approximately 3.0 to 3.2, and is generally non-fluorescent.
Optical Properties
Uniaxial negative with strong pleochroism in natural crystalline form, though appearing opaque in this carved, dense black polished state without visible transparency or double refraction.
Hardness & Durability
Origin Region
Brazil, Pakistan, Madagascar, USA (California and Maine), and various worldwide pegmatite localities
Hardness & Durability
Mohs hardness of 7 to 7.5, offering good durability and wearability for jewelry, though brittle and sensitive to severe thermal shock.
Care & Maintenance
Safe to clean with warm soapy water using a soft brush. Avoid harsh chemical cleaners, ultrasonic cleaners, and sudden extreme temperature changes.
Rarity & Value
Common and widely available worldwide; value is primarily determined by size, quality of raw material, and craftsmanship of the carving, generally ranging from inexpensive to moderately priced.
Special Characteristics
Displays strong pyroelectric and piezoelectric properties, generating an electrical charge when heated or subjected to mechanical pressure.
Lore & History
Historically used as a protective talisman against negative energies and environmental pollutants. In modern crystal healing, it is traditionally associated with the Root Chakra for grounding, protection, and psychic shielding, though these are cultural beliefs rather than scientifically proven claims.