2%
If we look at the Earth, accumulations of hydrocarbons, for example, cover far, far less than 2% of the surface.
Yet that mineral resource is the whole basis of our energy economy.
Do not denigrate something because it is rare on a planetary scale. If it offers energy efficiency, or raw materials feedstock, we can input 0.01% of a planet's surface and still have a viable industry...
The question to ask is "would it be economic to mine this resource, rather than flying-in the refined product?"