Nylon
Man-made
Water
Natural
Silk
Natural
Minerals
Natural
Metal
Natural
Synthetic rubber
Man-made
Gold
Natural
Leather
Both - It can be natural (made from animals) or synthetic (made from plastic to look like real leather)
Sand
Natural
Iron
Natural
Glass
Man-made
Rubber
Natural
Chalk
Natural
Plastic
Man-made
Concrete
Man-made
Soil
Natural
Coal
Natural
Air
Natural
Wood
Natural
Cotton
Natural
Steel
Man-made (it's a metal composed principally of iron and carbon)
Paper
Man-made
Ceramic
Natural
Polyester
Man-made