Elastic bracelet with 18–22 10mm black tourmaline (schorl) beads, sourced from Brazil. Black tourmaline is the black mineral par excellence in beaded jewelry: its polished vitreous luster, total opacity, and high hardness (7–7.5 Mohs) make it resistant to everyday scratching. 10mm beads have a good visual presence on the wrist without being excessively heavy, and the intense black color of tourmaline is deeper and more uniform than that of basalt or obsidian.
Item 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 cord |
| 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 total opacity and intense black color. Unlike basalt or obsidian, black tourmaline has a clear vitreous luster when mirror-polished: light reflects directly off the surface, without the matte dispersion of volcanic rocks. 10mm beads clearly show this difference: each sphere has a uniform brilliant finish.
In unpolished tourmaline crystals, longitudinal striations characteristic of the mineral's trigonal crystal system are often observed. In polished beads, these striations disappear under the mirror finish but can be discerned as slight variations in the surface when turning the bead under raking light. This microstructural detail confirms the genuine mineral origin of the beads.
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 magmatic fluids rich in boron and iron crystallize in the late stage of granite cooling. Brazil, especially the states of Minas Gerais and Paraíba, is the world's largest producer of lapidary-quality tourmaline, with deposits that include both black schorl and the most valued varieties (blue indicolite, pink rubellite, neon green Paraíba).
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. Prior to that distinction, black schorl was frequently confused with obsidian or jet in medieval European markets. In 17th-century Europe, jet (lignite) and black tourmaline were used as travel and protection amulets, a use that persisted until the 19th century in Victorian mourning jewelry.
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 as 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. Hardness (7–7.5 Mohs) is a clear discriminator: a steel key cannot scratch it, unlike glass (Mohs 5.5) or synthetic resin. The specific gravity of schorl (3.1–3.2 g/cm³) is higher than that of black glass (2.5 g/cm³).
Frequently Asked Questions
Is this tourmaline treated?
No detectable treatment. The intense black 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 cord allows the bracelet to adjust to 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 cord. Consult 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 crystal structure.
Can the bracelet get wet?
The mineral tolerates water without problems. The elastic cord can 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.
