Rock value: Scientific and economic conditions for collecting minerals in the early nineteenth century.

This article focuses on the mineral-collecting practices and scientific contributions of Carl Wilhelm Nose (1753–1835), a physician and prominent mineralogical expert in early nineteenth-century Germany. Nose amassed extensive rock collections, particularly from the Siebengebirge volcanic region, which he used to support the neptunism theory of earth's origin, arguing that basalt formed through water-related weathering rather than volcanic fire. His collections were systematically catalogued, circulated among scientific networks, sold, and ultimately donated to institutions such as the Royal Mineral Cabinet in Berlin and universities, reflecting the intertwined scientific, social, and economic values attributed to mineral specimens during the formative period of modern natural history museums. The article highlights how Nose's work exemplifies the transformation of natural objects into epistemic and economic assets within Enlightenment-era scientific and cultural contexts.