The provenance of objects –in terms of chronology of ownerships – in museums and collections is a cutting-edge topic discussed especially among art historians, historians and ethnologists. Until now, the emphasis is on works of art and cultural objects linked to either Nazi-confiscated art or to objects linked to a colonial context. Discussions about restitutions to legal successors or societies of origin engage scientific communities, feuilletons as well as the public. In geoscientific museums, the provenance of objects usually refers to the exact location of finding. Here, a broader, more critical approach is overdue as many geoscientific objects might have a similar critical background as the above-mentioned groups of objects. As mineralogical museum with several historical collections dating from the end of the 19th and beginning of the 20th century, we shed light on objects with a potentially colonial background. To begin with, we focus on minerals originating from the former German colonies in Africa. Like other museums worldwide, we host hundreds of specimens from Tsumeb in Namibia. The mine got established under German rule in the late 19th century. It did not only supply the German Empire with tons of ores, but also private collectors and museums worldwide with minerals for their collections. We began to review our inventory regarding the number of specimens, historical (previous ownerships) and chronological (moment of exploitation) background. We take a critical look into the past of our 200 years old institution and hence contribute to public and scientific discussions related to the provenance of objects in museums.