direct materials are all materials that form an inyegral part of the finished product and that are included explicitly in calculating the cost of the product. examples of direct materials are the lumber to make furniture and the crude oil to make gasoline. the ease with which the materials items can be traced to the final product is a major consideration in classifying items as direct materials. for example, the tacks in furniture form part of the finished product, but because the cost of the tacks required for each pece of furniture is trivial, they are classified as indirect materials.