WGNHS
Wisconsin Geological and Natural History Survey

Djurleite

Metallic djurleite in matrix with secondary copper minerals (green stains). From the Naesmark Mine, Amdals Verk, Tokke, Telemark, Norway. Sample is 2 x 3 cm. (Photo courtesy Knut Edvard Larsen; unauthorized reproduction is prohibited.)

Formula: Cu31S16 Monoclinic

Description:

Djurleite is a black massive mineral most often found as a supergene mineral in copper deposits. It is easily mistaken for chalcocite, hence frequently overlooked.

Heyl and others (1970, 1978) note it as occurring with chalcocite in the Upper Mississippi Valley zinc-lead district in Grant, Iowa, and Lafayette Counties, but give no locality information. A sample (NS.21977.003) in the UW–Madison Geology Museum has a black coating on pyrite from Mineral Point that was determined to be djurleite (Klaus Westphal, 1990, personal communication).