In the early years of the 17th century, European scholars became interested in the concealed parts of the Earth in relation to Antiquity collections and as windows onto the past. Caves started then to be viewed as actual cabinets of curiosities, where the double characteristic of the subterranean world as the meeting point of nature and culture became blatant. The paper examines the intermediating function of the subterranean world, its epistemology and the influence of early collections on the debates around the formation of cave minerals.