“Natural resources” are anything but.
I have said this before in the sense that everything we get from nature comes in an inconvenient form: metals must be extracted from their ores; grain must be milled or threshed and the wheat separated from its chaff; crude oil must be refined into its constituent weights.
But the more philosophical point is that all resources are the product of the human mind. A “natural” resource is only a resource at all in the context of a particular technology. It is only a resource to someone who can look at it and understand its use and value. And it is only a resource to someone who has the technology and the capital to extract it from its environment and put it to that use.
You can see this in the stories of the early development of industries.
Crawford then goes on to list and elaborate on resources that were once waste products: natural gas, portland cement and cast iron.