Clay slate with iron spar and quartz

Roughly the size of a fist, this mineral comes from the Eisenhardter Tiefbau mine in Eiserfeld-Eisern, not quite 8 km south of Siegen, that has been shut down since 1957. The light-coloured quartz rock has variously sized, angular parts of anthracite-grey clay slate embedded within it. Traces of iron spar can be recognised by their golden ochre colour. Iron spar, also known as siderite, was the most important iron ore in Siegerland and was mined here. The mineral collection from which this object originates had been set up by the Siegen Mining College for use in its mineralogy theory lessons. As time passed, the collection was expanded by gifts made by former mining students. Pit foremen, deputy pit foremen, senior pitmen and mine surveyors were all trained at the Siegen Mining College. This college was shut down when the Siegerland mines were closed in 1967, with part of the collection being acquired by the city of Siegen.