Alisonite is not an officially recognized mineral species. It was reported historically as a copper–lead sulfide (Cu₆PbS₄), but later studies suggest it is probably a mixture rather than a distinct mineral.
🌍 Origins and Naming
- Name Origin: Named after R.E. Alison, a geologist involved in its identification.
- Type Locality: Reported from the Grande Mine (La Marqueza Mine), Arqueros silver mining district, La Serena, Elqui Province, Coquimbo Region, Chile.
- Status: Not approved by the International Mineralogical Association (IMA).
🔬 Reported Properties
- Formula (proposed): Cu₆PbS₄
- Composition: Copper (~53%), lead (~29%), sulfur (~18%).
- Appearance: Metallic, dark-colored material.
- Habit: Reported as massive aggregates rather than distinct crystals.
- Hardness & Density: Not well established due to its uncertain status.
⚙️ Geological Context
- Found in silver mining districts of Chile.
- Likely represents an intergrowth or mixture of copper sulfides and lead sulfides rather than a discrete mineral phase.
- Associated with other sulfides in hydrothermal deposits.
📖 Scientific and Collector Significance
- Petrology: Interesting historically as an example of early misidentification in mineralogy.
- Collectors: Rarely seen; specimens labeled “alisonite” are usually mixtures and not considered valid species.
- Academic Note: Serves as a cautionary case in mineral classification—highlighting the importance of modern analytical techniques.
✨ Conclusion
Alisonite was described as a copper–lead sulfide from Chile, but it is not a valid mineral species. It is probably a mixture of sulfides, and today it is mainly of historical interest in mineralogy rather than scientific or collector significance.
In short: Alisonite = reported Cu–Pb sulfide from Chile, but not an approved mineral; likely a mixture.
