Any naturally occurring, finite resources that diminish with use, such as oil and coal. In terms of the human timescale, a nonrenewable resource cannot be renewed once it has been consumed. Most nonrenewable resources can only be renewed over geologic time, if at all. All the fossil fuels and mineral resources fall into this category. Renewable resources occur naturally and cannot be used up, such as solar energy or wave power. As resource depletion has become more common, the process of recycling has somewhat reduced reliance on virgin nonrenewable resources.