Djurleite-Chalcocite

specimen number:
8282434

location:
Ait Ahmane, Tansifte Caidat, Agdz Cercle, Zagora, Draa-Tafilalet, Morocco

description:

Outstanding thin platy semi lustrous metallic crystals to 3.5 cm in size across the top of a thin matrix. These crystals are interlayered with both species. This is in very good condition.

The Ait Ahmane mining area, located within the Zagora Province of the Draa-Tafilalet region in Morocco, is a significant locality situated in the eastern portion of the Bou Azzer cobalt-nickel district. Geologically, the deposit is hosted within a Neoproterozoic ophiolite complex that underwent intense hydrothermal alteration during the Hercynian orogeny. High-temperature, arsenide-rich hydrothermal fluids filled fractures and shear zones at the contacts between serpentinites and quartz-carbonate rocks, depositing massive structures of native silver, skutterudite, safflorite, and various copper-bearing sulfides. Localized mining and prospecting at Ait Ahmane began during the mid-twentieth century as part of the broader development of the Bou Azzer district, which saw systematic underground exploration expand in the 1950s and 1960s. Underground extraction of high-grade cobalt and nickel ore has continued intermittently through various production phases and exploration campaigns right up into the early twenty-first century.

The djurleite - chalcocite series represents a group of closely related, low-temperature copper sulfide minerals that are critical components of supergene enrichment zones in copper deposits. Geologically, these minerals form primarily in the upper oxidized sections of copper ore bodies where downward-percolating, copper-rich solutions react with primary iron-copper sulfides like chalcopyrite or bornite. While chalcocite crystallizes in the monoclinic system at room temperature, djurleite is slightly copper-deficient, resulting in subtle differences in their atomic arrangements and physical stability. Because they share almost identical dark gray to black metallic properties, a soft composition, and similar dense, massive habits, distinguishing between members of this mineral series often requires detailed X-ray diffraction or electron microprobe analysis.

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