Cu5FeS4Cu4MoS6

Cu5FeS4Cu4MoS6 is a complex sulfide mineral belonging to the group of copper-iron-molybdenum sulfides. It is a rare and recently identified mineral, first described in 2019 from specimens found in the Kola Peninsula, Russia, specifically within the Lovozero alkaline massif. The mineral forms as a secondary phase in pegmatitic rocks, often associated with other sulfides like chalcopyrite (CuFeS2) and molybdenite (MoS2).

The chemical composition of Cu5FeS4Cu4MoS6 reflects its mixed metallic and chalcogenide nature, combining copper (Cu), iron (Fe), molybdenum (Mo), and sulfur (S). Its structure is characterized by a layered arrangement of metal atoms and sulfide ions, which contributes to its unique physical properties. The mineral exhibits a metallic luster and is typically dark-colored, often appearing bronze or grayish-black in hand specimens. Its hardness is relatively low, around 3–4 on the Mohs scale, making it relatively soft compared to many other sulfide minerals.

Cu5FeS4Cu4MoS6 is of interest to mineralogists due to its unusual composition and structural complexity. It provides insights into the behavior of transition metals in sulfide systems, particularly under conditions found in alkaline igneous environments. While not yet widely recognized in mineral collections or industrial applications, its discovery expands the known diversity of sulfide minerals and contributes to the understanding of ore-forming processes in alkaline rocks. Further research may clarify its stability, occurrence, and potential significance in geological studies.