(i) Native ores:
Silver, gold, platinum etc., are found in native state in the earth’s crust.
(ii) Oxide ores:
An ore in which a metal occurs as an oxide is called an oxide ore.
For example, bauxite (A1203.2H20), hematite (Fe203), pyrolusite (Mn02)
(iii) Sulphide ores:
An ore in which a metal occurs as sulphide is called a sulphide ore. For example, Iron pyrites (FeS), Galena (PbS), Copper pyrites (CuFeS2), Cinnabar (HgS).
(iv) Carbonate ores:
An ore in which a metal occurs as carbonate or basic carbonate is called a carbonate ore. For example, limestone (CaCOg), dolomite (CaC03, MgC03)
(v) Halide ores:
Aluminium occurs as a fluoride, e.g., cryolite (Na3AlFg). Sodium and potassium occur as chloride, e.g., carnallite (KC1, MgCl2.6H20), rocks salt (NaCl).
(vi) Sulphate ores:
Barium and lead occur as barites (BaS04) and anglesite (PbS04) respectively.