Black Tourmaline
Schorl · Mineral Specimen and Semi-Precious Gemstone.
Crystal System
Trigonal crystal system, typically forming prismatic crystals with vertical striations.
Mineral Group
Cyclosilicate subgroup within the Silicate mineral class.
Chemical Formula
NaFe3+2Al6(Si6O18)(BO3)3(OH)4
Formation Process
Forms primarily in pegmatites and hydrothermal veins, as well as in metamorphic rocks like schists and gneisses.
About This Crystal
An opaque black mineral specimen showing characteristic deep striations running parallel to the elongation of the crystal prism, with a submetallic to vitreous luster.
Physical Characteristics
Color is solid black with a white streak, uneven to conchoidal fracture, distinct cleavage is absent, specific gravity ranges from 3.0 to 3.2, and it is brittle.
Optical Properties
Uniaxial negative with strong birefringence and notable pleochroism.
Hardness & Durability
Origin Region
Found globally with notable deposits in Brazil, Madagascar, Pakistan, Afghanistan, and the United States (California, Maine).
Hardness & Durability
Mohs hardness of 7 to 7.5, moderate toughness, and generally stable against most chemicals.
Care & Maintenance
Can be cleaned safely with warm soapy water, avoiding harsh acids and extreme thermal shock.
Rarity & Value
Very common mineral, highly affordable as a mineral specimen, generally untreated.
Special Characteristics
Exhibits strong pyroelectric and piezoelectric properties, generating an electrical charge when heated or compressed.
Lore & History
Widely used in modern crystal healing as a premier grounding stone and for energetic protection, associated with the root chakra.