Phosphates & Oxides
Sulfide
What it is
Minerals where metals bond with sulfur instead of oxygen. Pyrite (fool's gold) is iron sulfide with a metallic luster. Galena is lead sulfide, the primary ore of lead. Chalcopyrite is copper-iron sulfide with an iridescent tarnish.
How it forms
Forms in hydrothermal veins, volcanic fumaroles, and sedimentary environments where sulfur-reducing bacteria create the right chemistry. Pyrite cubes can form perfectly in sedimentary muds.
Metal + Sulfur (XS, XS₂)
