Tourmaline Rough - Height: 16 cm - Width: 12 cm- 2 kg - (1)
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Description from the seller
1. Overview
This natural black tourmaline (schorl variety) is presented for auction in a polished-trunk format, a large piece with strong visual presence, sourced from an old stock.
This is not industrial decorative material nor a recent production. It is a solid piece, selected for quality, crystal structure, and mineralogical aesthetics, suitable for both a serious collection, high-end decorating, or as a tangible mineral asset.
Black tourmaline is today one of the minerals in highest demand and, at the same time, one of the most affected by imitations, composites, and treated materials. Large and authentic pieces, especially from older batches, are increasingly scarce in the international market.
2. Dimensions and weight
Weight: 2 kg
Total height: approx. 16 cm
Length of the trunk: approx. 18 cm
Base: approx. 12 × 9 cm
Dimensions consistent with a solid piece, not hollow or reconstituted.
3. Mineralogical identification
Mineral name: Black tourmaline (Schorl)
Group: Cyclosilicates
Chemical formula:
NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄
The dominant presence of iron is responsible for the intensely black color characteristic of schorl.
4. Physical properties
Crystal system: Trigonal
Hardness (Mohs): 7 – 7.5
Theoretical density: approx. 3.0–3.3 g/cm³
Crystal habit: elongated prismatic with longitudinal striations
These properties fully match the piece presented.
5. Visual and Geological Reading
The piece exhibits natural longitudinal striations, well-defined prismatic growth, and polished surfaces that allow the true internal structure of the crystal to be appreciated.
The luster, texture, and response to light are consistent with authentic tourmaline and not with glass, resin, or sintered materials.
It does not exhibit bubbles, artificial pores, or suspicious areas typical of modern composites.
6. Authenticity and tests carried out
In a market saturated with counterfeits, the following verification criteria have been taken into account:
Test with acetone: no color transfer (rules out surface dyes).
Magnified observation: compact structure, with no pores or artificially formed internal bubbles.
Weight and feel: consistent with the actual density of schorl.
Hardness: compatible with natural tourmaline.
Reasonable conclusion: authentic natural black tourmaline, with no indications of treatments or additives.
7. Origin and probable provenance
Usual origin and compatible with this type of pieces: Madagascar, one of the major historical producers of quality tourmaline.
The older shipments come from extractions prior to the current surge in mass production and industrial processing.
8. History of the mineral
Tourmaline has been known since antiquity, although its scientific identification was consolidated in the eighteenth century. For centuries it was confused with other gems, which already indicates its complexity and mineral richness.
Currently, black tourmaline is especially valued by collectors, interior designers, and buyers who seek authentic minerals with real physical presence, as opposed to decorative pieces with no mineral value.
9. Old remittance and market context
This piece comes from an old batch, dating from before the boom in imitations, reconstituted and artificial materials.
Today, large pieces of authentic tourmaline are becoming increasingly difficult to obtain, and their price tends to rise, especially in well-informed international markets.
10. Value as an investment
In the current context of inflation, scarcity of raw materials, and a saturation of counterfeits, authentic, substantial, and verifiable minerals are considered tangible assets with potential for appreciation.
This piece brings together the key factors: size, authenticity, provenance, and an antique shipment.
11. Condition of preservation
Condition: excellent
Well-polished surfaces.
No structural cracks or repairs.
Stable and solid piece.
12. Recognition of work at the source
This piece is the result of the hard work of the miners at the source, who operate in challenging conditions to extract materials that today form part of mineral collections and heritage.
13. Positioning and sales policy
This is not a clearance sale, nor generic decorative material.
This piece is presented with a positioning of quality, expertise, and sound judgment, in keeping with its nature and the current international market.
14. Care and maintenance
Avoid direct blows
Clean only with a dry or slightly damp cloth.
Do not expose to aggressive chemicals.
Keep it in a stable place if used as a collectible or decorative piece.
15. Conclusion
Authentic natural black tourmaline (schorl), large in size, from an old batch, with a clear geological signature, authenticity tests conducted, and strong aesthetic and mineralogical value.
A solid piece for collectors, upscale decor, or investment in authentic minerals, in a market increasingly dominated by artificial materials.
1. Overview
This natural black tourmaline (schorl variety) is presented for auction in a polished-trunk format, a large piece with strong visual presence, sourced from an old stock.
This is not industrial decorative material nor a recent production. It is a solid piece, selected for quality, crystal structure, and mineralogical aesthetics, suitable for both a serious collection, high-end decorating, or as a tangible mineral asset.
Black tourmaline is today one of the minerals in highest demand and, at the same time, one of the most affected by imitations, composites, and treated materials. Large and authentic pieces, especially from older batches, are increasingly scarce in the international market.
2. Dimensions and weight
Weight: 2 kg
Total height: approx. 16 cm
Length of the trunk: approx. 18 cm
Base: approx. 12 × 9 cm
Dimensions consistent with a solid piece, not hollow or reconstituted.
3. Mineralogical identification
Mineral name: Black tourmaline (Schorl)
Group: Cyclosilicates
Chemical formula:
NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄
The dominant presence of iron is responsible for the intensely black color characteristic of schorl.
4. Physical properties
Crystal system: Trigonal
Hardness (Mohs): 7 – 7.5
Theoretical density: approx. 3.0–3.3 g/cm³
Crystal habit: elongated prismatic with longitudinal striations
These properties fully match the piece presented.
5. Visual and Geological Reading
The piece exhibits natural longitudinal striations, well-defined prismatic growth, and polished surfaces that allow the true internal structure of the crystal to be appreciated.
The luster, texture, and response to light are consistent with authentic tourmaline and not with glass, resin, or sintered materials.
It does not exhibit bubbles, artificial pores, or suspicious areas typical of modern composites.
6. Authenticity and tests carried out
In a market saturated with counterfeits, the following verification criteria have been taken into account:
Test with acetone: no color transfer (rules out surface dyes).
Magnified observation: compact structure, with no pores or artificially formed internal bubbles.
Weight and feel: consistent with the actual density of schorl.
Hardness: compatible with natural tourmaline.
Reasonable conclusion: authentic natural black tourmaline, with no indications of treatments or additives.
7. Origin and probable provenance
Usual origin and compatible with this type of pieces: Madagascar, one of the major historical producers of quality tourmaline.
The older shipments come from extractions prior to the current surge in mass production and industrial processing.
8. History of the mineral
Tourmaline has been known since antiquity, although its scientific identification was consolidated in the eighteenth century. For centuries it was confused with other gems, which already indicates its complexity and mineral richness.
Currently, black tourmaline is especially valued by collectors, interior designers, and buyers who seek authentic minerals with real physical presence, as opposed to decorative pieces with no mineral value.
9. Old remittance and market context
This piece comes from an old batch, dating from before the boom in imitations, reconstituted and artificial materials.
Today, large pieces of authentic tourmaline are becoming increasingly difficult to obtain, and their price tends to rise, especially in well-informed international markets.
10. Value as an investment
In the current context of inflation, scarcity of raw materials, and a saturation of counterfeits, authentic, substantial, and verifiable minerals are considered tangible assets with potential for appreciation.
This piece brings together the key factors: size, authenticity, provenance, and an antique shipment.
11. Condition of preservation
Condition: excellent
Well-polished surfaces.
No structural cracks or repairs.
Stable and solid piece.
12. Recognition of work at the source
This piece is the result of the hard work of the miners at the source, who operate in challenging conditions to extract materials that today form part of mineral collections and heritage.
13. Positioning and sales policy
This is not a clearance sale, nor generic decorative material.
This piece is presented with a positioning of quality, expertise, and sound judgment, in keeping with its nature and the current international market.
14. Care and maintenance
Avoid direct blows
Clean only with a dry or slightly damp cloth.
Do not expose to aggressive chemicals.
Keep it in a stable place if used as a collectible or decorative piece.
15. Conclusion
Authentic natural black tourmaline (schorl), large in size, from an old batch, with a clear geological signature, authenticity tests conducted, and strong aesthetic and mineralogical value.
A solid piece for collectors, upscale decor, or investment in authentic minerals, in a market increasingly dominated by artificial materials.
Details
Number of items
1
Main Mineral
Tourmaline
Mineral Form
Rough
Weight
2 kg
Country of Origin
Madagascar
Height
16 cm
Width
12 cm
Depth
10 cm
Sold by
Disclaimer
It is believed that certain gemstones and minerals have beneficial health and spiritual properties. However, using or wearing gemstones or minerals does not mean that you can treat, cure or prevent any disease. Please consult your health care professional for information on health care issues and do not stop any medications or courses of treatment, without first consulting your health care professional. The use of gemstones or minerals as a wellness therapy is one of personal choice. While stones or crystals have been used historically to relieve or prevent symptoms, the objects sold on our website offer no guarantee of results. Therefore, Catawiki cannot guarantee or be held liable for the effectiveness of these objects sold herein.
It is believed that certain gemstones and minerals have beneficial health and spiritual properties. However, using or wearing gemstones or minerals does not mean that you can treat, cure or prevent any disease. Please consult your health care professional for information on health care issues and do not stop any medications or courses of treatment, without first consulting your health care professional. The use of gemstones or minerals as a wellness therapy is one of personal choice. While stones or crystals have been used historically to relieve or prevent symptoms, the objects sold on our website offer no guarantee of results. Therefore, Catawiki cannot guarantee or be held liable for the effectiveness of these objects sold herein.
