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Large tumbled black tourmaline (schorl variety) from Brazil. Size between 40 and 58 mm, weight between 44 and 74 grams: volumetric format for hand stones, large pocket stones, or as a central piece in large format macramé.
Material Data Sheet
| Mineral |
Black Tourmaline (Schorl) — borosilicate from the tourmaline group |
| Color |
Opaque intense black with vitreous luster on polished surfaces |
| Size |
40-58 mm diameter; 44-74 g weight per piece |
| Shape |
Tumbled; "river pebble" finish with no sharp edges |
| Finish |
Smooth polished, characteristic of tumbled stones |
| Hardness |
7-7.5 Mohs — very scratch resistant; the tumbled format neutralizes the fragility of raw crystal |
| Origin |
Brazil (Minas Gerais) |
| Treatment |
Untreated. The black color comes from the native iron and manganese in the mineral (schorl) |
| Piece Type |
Unique shape for each tumbled stone; intuitive selection within the size range |
Why the Tumbled Format
Raw tourmaline crystal presents in prisms with marked cleavage planes; although hardness is high, points are prone to breaking with regular handling. The tumbled finish eliminates these fragile points, leaving a continuous surface resistant to daily use — the most practical version to carry by hand or as a large format centerpiece.
What This Format is Good For
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Large Format Macramé — the 44-74 g weight is ideal for statement pendants with thick waxed thread; the ergonomic shape can be tied directly without a cap.
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Wire Wrap — high hardness allows for thick gauges (1-1.5 mm) without marring the polished surface.
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Pocket Stone / Hand Stone — the 40-58 mm size fits in the palm like a worry stone; associated with protection and grounding.
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Decorative Compositions and Altars — the visual mass and intense black create a striking focal point against light surfaces.
Black Tourmaline in Tradition
Tourmalines are piezoelectric and pyroelectric: when rubbed or heated, they generate a weak electrical charge. 18th-century Dutch sailors used it to clean ash from pipes, taking advantage of this electrical property ("aschentrekker," ash-puller). In crystal tradition, it is associated with personal protection and grounding.
The symbolic properties attributed to minerals belong to cultural and historical traditions. They are shared for educational purposes, not as medical advice or a substitute for professional care.
Frequently Asked Questions
Why the tumbled format and not raw crystal?
Tumbling neutralizes the fragile points of the prism and leaves a continuous, resistant surface for carrying in a pocket or as a hand stone.
How much does each tumbled stone weigh?
Between 44 and 74 grams depending on size. The weight is notable due to tourmaline's high density (3.0-3.2 g/cm³).
Is it really piezoelectric?
Yes, all tourmalines are piezoelectric and pyroelectric — they generate a weak charge with mechanical pressure or temperature changes, measurable with instruments.
How do you care for it?
Clean with a soft, slightly damp cloth. Scratch-resistant in normal use; avoid sudden impacts on the edges. More in jewelry care.
More about black tourmaline: properties, meaning, and uses. See also: all tumbled stones · meditation stones.
