Elastic bracelet with 18–22 10mm black tourmaline (schorl) beads, sourced from Brazil. Black tourmaline is the quintessential black mineral in bead jewelry: its polished vitreous luster, complete opacity, and high hardness (7–7.5 Mohs) make it resistant to everyday scratching.
Piece Details
| Mineral |
Black Tourmaline — Schorl (NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄) |
| Bead Size |
10 mm diameter (±0.5 mm) |
| Number of Beads |
18–22 units depending on wrist size |
| Finish |
Mirror Polished — Vitreous Luster |
| Hardness |
7–7.5 Mohs |
| Clasp |
No clasp — adjustable elastic thread |
| Origin |
Brazil |
| Treatment |
Untreated |
| Type |
Multi-unit — natural mineral beads |
The Beads in Detail
Schorl is the most abundant variety of the tourmaline group, with an iron-rich composition that produces its characteristic complete opacity and intense black color.
In unpolished tourmaline crystals, it is common to observe longitudinal striations characteristic of the mineral's trigonal crystal system.
How Black Tourmaline Forms
Tourmaline is a complex borosilicate that crystallizes in the trigonal system in pegmatitic granites and high-grade metamorphic rocks. Schorl — the iron-rich variety — forms when boron and iron-rich magmatic fluids crystallize in the late stage of granite cooling.
Tourmaline in Lapidary Tradition
Tourmaline was first classified as a distinct mineral in the 18th century, when Ceylonese traders distinguished it from other dark stones. Before that distinction, black schorl was often confused with obsidian or jet in medieval European markets.
In crystal tradition, black tourmaline is associated with energetic protection, grounding, and boundary setting — qualities linked to its opaque black color and density. This is shared as cultural reference, not medical advice.
How to Recognize Genuine Black Tourmaline
Genuine black tourmaline has a clear vitreous luster when polished, distinct from the curved vitreous appearance of obsidian or the matte finish of basalt. In unpolished crystals, the characteristic longitudinal striations of the trigonal system are an unmistakable signature.
Frequently Asked Questions
Is this tourmaline treated?
No detectable treatment. The intense black color comes from the high iron content (Fe²⁺/Fe³⁺) of the schorl variety, without dyeing or irradiation. Statement based on lapidary observation; the piece does not include formal gemological certification.
Is the bracelet one size fits all?
Yes. The elastic thread allows the bracelet to fit most wrist sizes (16–21 cm circumference). The number of beads varies between 18 and 22 units; the diameter of each bead is 10 mm ±0.5 mm.
How do you care for a black tourmaline bracelet?
The high hardness (7–7.5 Mohs) makes the beads resistant to everyday scratching. Clean with a soft, damp cloth. Avoid harsh detergents and prolonged exposure to water to preserve the elastic thread. See our jewelry care guide.
What is the difference between black tourmaline, obsidian, and basalt?
Black tourmaline (crystalline mineral, Mohs 7–7.5) is harder and has a clearer vitreous luster than obsidian (volcanic glass, Mohs 5–5.5) and much more uniform than basalt (porous rock, Mohs 5–6). Schorl is the only one of the three that is a real mineral with a defined crystalline structure.
Can the bracelet get wet?
The mineral itself handles water without issue. The elastic thread may deteriorate with repeated immersion. We recommend removing the bracelet when swimming or showering.
Does black tourmaline have piezoelectricity?
Yes. Tourmaline as a mineral group exhibits piezoelectricity and pyroelectricity — it generates a small electrical charge when mechanically deformed or heated. This property is well-documented in geophysics and has applications in industrial pressure sensors. In polished beads used in jewelry, the effect is not practically perceptible.
See also: mineral bracelet collection · raw tourmaline.
