How does re-fertilizer work regarding rocks?

I know that re-fertilizer will re-grow plants, trees, and rocks that were previously harvested in a small radius from where it's placed.

Does this work on any type of rock, even oil, obsidian, crystal, etc?
Is it the exact same resource that was previously harvested? Will it yield the same types and amounts of resources? For example, if a crystal gives me a rare mushroom, will it do so again after being refertilized?