History · Geology
About Tunaberg
Tunaberg in Södermanland, Sweden is the type locality for cobaltite (CoAsS) — described by Swedish mineralogist Anders Brongniart from this deposit in 1832. The mining district was active from the 16th to the 19th centuries.
Geology
The deposit is a Proterozoic Cu-Co-Fe skarn in dolomitic marbles intruded by granitoid bodies. Cobaltite, chalcopyrite and magnetite formed in pyroxene-amphibole-bearing skarn assemblages with characteristic Co-As enrichment.
Notable Minerals
Cobaltite (sharp pyritohedral and modified-cubic crystals — type quality), chalcopyrite, magnetite, calcite (gem-clear rhombs), tremolite, dolomite, pyrrhotite. Old Tunaberg cobaltite octahedra command historical-Swedish-mineralogy provenance value.
Collector Notes
Tunaberg specimens are central to European Co-mineralogy collection. Pair with Cobalt (Ontario) and Bou Azzer (Morocco) for the world’s Co-mineral collector triad.
Minerals Produced Here
- Calcite (方解石)
- Chalcopyrite (黄铜矿)
- Cobaltite (辉砷钴矿)
- Dolomite (白云石)
- Magnetite (磁铁矿)
- Pyrrhotite (磁黄铁矿)
- Tremolite (透闪石)
