XL tumbled black tourmaline (Schorl) in XL format, 64-99 mm, available in 5 pieces with individual measurements: A (99×52×43 mm), B (81×58×29 mm), C (80×50×53 mm), D (64×56×30 mm) and E (80×73×38 mm). Complex borosilicate polished in a lapidary tumbler, from Brazil.
Piece details
| Mineral |
Black Tourmaline — Schorl (NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄) |
| Dimensions |
A: 99×52×43 mm · B: 81×58×29 mm · C: 80×50×53 mm · D: 64×56×30 mm · E: 80×73×38 mm · ±0.5 mm |
| Shape and back |
XL tumbled, freeform, irregular convex back |
| Finish |
Tumbled polished (satin with matte areas characteristic of the mineral) |
| Hardness |
7-7.5 Mohs — very wear-resistant; suitable for intensive use |
| Origin |
Brazil |
| Treatment |
Untreated |
| Piece type |
5 options with individual measurements (select when ordering) |
These specific pieces
XL black tourmaline has a presence that standard tumbled stones cannot match: the mass is sufficient to feel the weight in the hand (the larger pieces exceed 200 g), and the polished surface reveals a black that is not entirely homogeneous —the prismatic structure of Schorl leaves some areas with a livelier shine and others with a more matte finish, depending on the orientation of the prisms with respect to the polished surface.
The five sizes correspond to five individual polished crystals, not a statistical range: the exact measurements indicated are those of the specific piece available in each variant.
How black tourmaline is formed
Schorl is the most common variety of the tourmaline family and the most abundant tourmaline group mineral in the Earth's crust. It forms in granitic pegmatites —masses of very coarse-grained igneous rock that crystallize slowly at great depth— where slow cooling allows for the growth of large crystals.
Uses of XL black tourmaline tumbled stones
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Collection and decoration — the jumbo size makes them display pieces with their own identity. The intense black creates an effective contrast with white or translucent minerals.
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Working palmstone — the weight and polished surface make these tumbled stones a high-quality tactile object; their mass allows them to gradually absorb heat from the hand.
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Workshop reference — crystals of this magnitude are useful for studying the prismatic structure of tourmaline before planning cuts or carvings in smaller material.
Black tourmaline in lapidary tradition
Schorl is the most abundant tourmaline and historically has had less gemological value due to its opaque color, in contrast to green tourmaline (verdelite) or bicolor (watermelon).
In crystal tradition, black tourmaline is one of the minerals most associated with protection and grounding. It is considered a stone of boundaries and a protective field, used in geobiology practices by placing pieces in the corners of rooms.
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.
How to recognize genuine black tourmaline
Genuine black tourmaline has a visible prismatic structure inside under glancing light: small striations parallel to the original crystal axis that polishing smooths but does not completely eliminate. The black is not perfectly uniform throughout the piece —areas with higher iron density are darker.
Frequently asked questions
Are the indicated measurements exact for each variant?
Yes. The measurements for each variant (A, B, C, D, E) correspond to the actual dimensions of that specific piece measured in the workshop. They are not ranges but individual measurements, with a tolerance of ±0.5 mm due to the nature of the manual measurement process.
How much does each piece weigh?
The weight varies between approx. 100 g (variant D) and more than 250 g (variant A) depending on the volume. If you need the exact weight, please contact us before placing your order.
Is it suitable for meditation palmstone?
Yes. The size and weight of these pieces make them especially suitable for this use. The tumbled polished surface is smooth and the mineral gradually warms with the heat of the hand.
More about tourmaline: properties, meaning and uses. See also: tumbled stones · lapidary cabochons.
