What must happen for a natural resource to become a synthetic material?

It needs to be pounded very thin.
It needs to go through a phase change.
It needs to go through a chemical reaction.
It needs to be dried out.

It needs to undergo a chemical process by which its molecular structure is changed or manipulated in order to create a new material with different properties than the original natural resource. This can involve combining the natural resource with other substances or applying heat, pressure, or other methods to alter its composition.