Non-mineralized metamorphic rocks(b,c)

Adventitiously introduced metals and grinding grit, dried immersion oil and amalgam(a)

Unmineralized intermediate rocks(f)

Minor sulphide mineralization in granite(c)

Manganese minerals(c-f)

Clay ironstones and oolitic iron ores(b-f)

Iron formations and bauxite(a-c)

Mississippi Valley-style lead-zinc deposits(a)