As a result of rising costs of labor, energy, and mining and processing equipment, the average unit price of construction aggregate has been on the rise over the last many years. However, the increase is not very phenomenal. The average cost of aggregate is $35 per ton. Transportation is a major factor in the delivered price of crushed stone which like angular rock is a form of construction aggregate. The cost of moving crushed stone from the plant to the market either equals or exceeds the sale price of the product at the plant. It is distinct from gravel which is produced by natural processes of weathering and erosion, and typically has a more rounded shape.