1) Sulfide mineral 
Valleriite is an uncommon sulfide mineral (hydroxysulfide) of iron and copper with formula: 4(Fe,Cu)S·3(Mg,Al)(OH)2 or (Fe2+,Cu)4(Mg,Al)3S4(OH,O)6. It is an opaque, soft, bronze-yellow to brown mineral which occurs as nodules or encrustations. ==Discovery and occurrence== Valleriite was first described in 1870 from an occurrence in Västmanland, ...