Weilite
Weilite is a rare copper iron sulfide mineral with the chemical formula CuFeS2. It is dimorphous with chalcopyrite, meaning it has the same chemical formula but a different crystal structure. Weilite crystallizes in the orthorhombic system, while chalcopyrite is tetragonal.
Weilite is typically found in hydrothermal ore deposits and metamorphic rocks, often associated with other sulfide minerals such as chalcopyrite, pyrite, and pyrrhotite. It forms as a result of low-temperature alteration of these other sulfide minerals.
Visually, weilite is characterized by its metallic luster and brass-yellow to bronze-yellow color. It can be difficult to distinguish from chalcopyrite without careful observation and analysis. Weilite is generally opaque.
Due to its rarity, weilite is not an economically important ore mineral for copper or iron. It is primarily of interest to mineral collectors and researchers studying sulfide mineralogy and ore genesis.