Black Tourmaline (Schorl)
Schorl · Mineral Specimen and Semi-Precious Decorative Stone
Crystal System
Trigonal, typically occurring as prismatic crystals with striated faces, massive, or columned aggregates, shaped here as a polished cabochon/tumble
Mineral Group
Silicates (Cyclosilicates)
Chemical Formula
NaFe3+2Al6(Si6O18)(BO3)3(OH)4
Formation Process
Igneous and hydrothermal processes, primarily crystallizing in granite pegmatites and high-temperature hydrothermal veins under moderate to high temperatures and pressures
About This Crystal
The specimen is a polished, deep opaque black stone with a smooth, glossy surface and high luster, reflecting light brightly across its polished facets and contours, showing no visible internal inclusions or color zoning
Physical Characteristics
Opaque black body color, colorless streak, conchoidal to uneven fracture, specific gravity around 3.20 to 3.26, brittle tenacity, and no notable fluorescence under standard UV light
Optical Properties
Singly or doubly refractive with strong birefringence, uniaxial negative, typically strongly pleochroic in raw crystalline forms, but appearing completely opaque black in this polished state
Hardness & Durability
Origin Region
Found globally with notable deposits in Brazil, Pakistan, Madagascar, the United States, and Africa; typically forms in pegmatites and hydrothermal veins
Hardness & Durability
Mohs hardness of 7 to 7.5, fair toughness due to lack of distinct cleavage planes, making it moderately durable and suitable for various types of jewelry if handled with care
Care & Maintenance
Safe to clean with warm soapy water and a soft brush; avoid harsh chemicals, ultrasonic cleaners, and extreme thermal shock; store separately to prevent scratching softer stones
Rarity & Value
Common and widely available, value is relatively low for polished stones and specimens unless incorporated into high-end jewelry or possessing exceptional crystal matrix formations; generally untreated
Special Characteristics
Exhibits strong pyroelectric and piezoelectric properties, generating an electrical charge when heated or compressed
Lore & History
Historically used as an amulet for protection against negative energies and psychic attack; in modern crystal healing, it is heavily associated with the root chakra for grounding, protection, and clearing stagnant energy