Copper(I) sulfide is a chemical compound with the formula Cu2S. It consists of copper in the +1 oxidation state and sulfide ions. This compound is typically found in nature as a mineral called chalcosine, which is an important source of copper. In terms of properties, copper(I) sulfide is a black solid that is insoluble in water. It can be used in various applications, including the production of copper metal through smelting processes. Additionally, it has potential uses in semiconductor technology due to its unique electrical properties.