iron filings are made of small pieces of iron & iron is always magnetic ->  iron fillings are always magnetic  iron fillings are always magnetic & sand is always nonmagnetic ->  a mixture of iron fillings and sand is a mixture of magnetic and nonmagnetic material  a mixture of iron fillings and sand is a mixture of magnetic and nonmagnetic material & magnet can be used for separating a magnetic material from a mixture of a magnetic and nonmagnetic material -> a magnet can be used to separate iron fillings from sand