Large raw black tourmaline (schorl) pieces, directly from Brazilian deposits. Two formats: 14 (118×55×32 mm) and 15 (89×67×45 mm). Prismatic crystals with characteristic longitudinal striations and vitreous-resinous luster. For mineralogical collection and decoration.
Piece Details
| Mineral |
Black Tourmaline — Schorl (sodium, iron, and aluminum cyclosilicate) |
| Dimensions |
Format 14: 118×55×32 mm · Format 15: 89×67×45 mm (±5 mm raw) |
| Condition |
Raw — natural crystalline surfaces without lapidary intervention |
| Finish |
Crystalline faces with vitreous luster; fracture surfaces with resinous luster |
| Hardness |
7–7.5 Mohs |
| Origin |
Brazil (Minas Gerais) |
| Treatment |
Untreated — crystal in natural state |
| Piece Type |
Unique piece per variant |
This specific piece
Raw black tourmaline has an unmistakable morphology: crystals with a triangular-trigonal cross-section and parallel vertical striations running the entire length of the prism. These striations are the structural hallmark of tourmaline, generated during crystal growth in pegmatite. The 89-118 mm pieces are suitable for a table or collection shelf: the opaque black with a luster between vitreous and resinous captures light differently depending on the angle. Mica may appear as shiny lamellae on fracture surfaces — a characteristic of Brazilian deposits, not a defect.
How schorl forms
Schorl forms in pegmatites — slow-crystallizing rocks with a high concentration of rare elements. During the solidification of Brazilian pegmatites (450-600 million years ago), boron, iron, and aluminum combined to form trigonal schorl crystals. The black color is due to the high iron content in the cyclosilicate structure. Large pieces only form in large-volume, slow-crystallizing pegmatites, making them relatively rare.
Intended uses
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Mineralogical collection — raw schorl of good size is a standard specimen in mid-to-high-level collections. The 89-118 mm pieces are "cabinet specimens." The striated prismatic morphology is representative of the tourmaline group.
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Interior decoration — the intense black with vitreous luster creates a strong visual contrast in modern or Nordic settings.
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Wire wrapping on raw crystal — the prismatic shape with striations offers a natural grip for metal wire in statement pendants.
Black tourmaline in history
Schorl was known in medieval Europe as "turmal." In the 18th century, European mineralogists classified tourmalines as their own mineral group upon discovering their piezoelectricity and pyroelectricity — the ability to generate an electrical charge with pressure or temperature variation. In crystal tradition, schorl is associated with protection and grounding. Symbolic properties are part of a cultural tradition. They do not constitute medical advice.
Frequently asked questions
What is the difference between schorl and other tourmalines?
Tourmalines are a mineral group with the same crystal structure but different compositions. Schorl is the iron-rich, black variety. Other varieties: rubellite (pink, manganese), verdelite (green, chromium), indicolite (blue). 95% of all tourmaline in the world is schorl.
Are these unique pieces?
Yes. Each variant (format 14 and 15) is a unique piece. The indicated dimensions correspond to that specific piece. Being raw crystals, each one has its own morphology.
Is it treated?
Untreated. The crystal is in its natural state as extracted from the deposit. The intense black color is the natural composition of iron-rich schorl.
How to recognize genuine schorl?
Three unmistakable marks: longitudinal striations on the prism faces, trigonal cross-section, and hardness 7–7.5 Mohs (scratches glass easily). Black glass and obsidian lack striations and have a different conchoidal fracture.
How to care for raw tourmaline?
Avoid impacts on terminations and fracture areas. To clean dust, use a soft brush and lukewarm water. Avoid aggressive detergents and acids. Consult our care guide.
See also: raw minerals collection · tumbled black tourmaline.
