@Marakus @sapphire @Aether You think it's harder to get high purity silicon from beach sand than it is to extract trace metals from hard rock deposits a couple thousand feet underground? Because we do the latter every day, all over the world.

It may be slightly more expensive to use non-ideal sources, but it's rank bullshit to claim it can't be done pretty easily. The companies who claim they need some super special feedstock are just snake oil salesmen.