— Copper is much rarer, but fortunately can be found in high-grade ores (ones containing a high percentage of copper) in particular places. Because copper is a valuable metal, it is also worth extracting it from low-grade ores as well. Ores are commonly oxides, for example: bauxite (Al 2 O 3) haematite (Fe 2 O 3) rutile (TiO 2). . . or sulfides ...