The definition of a natural resource is something that is found in nature that is useful to humans. All natural resources are finite, meaning once they are used, they cannot be replaced. Many valuable natural resources, such as gold and oil, have been nearly depleted, while others are still abundant.
Common natural resources include trees, rocks, minerals, crude oil, fossil fuels, zinc, iron ore, lead and copper. Things such as sunlight, water and air are also considered to be natural resources, although these things do not have a monetary value. However, something such as water can be used to produce energy, which does have a monetary value.