You’re probably thinking of the “rare earth” metals. Chile has over twice as much lithium as China. The oceans contain about 100,000 times as much. We’re not going to run out of this stuff — we’re just seeing the price mechanism kicking into gear. Higher prices lead to increased supply (and reduced demand); and, eventually a new (temporary) equilibrium. Just as fracking soon burst the oil and gas price bubbles; we can expect some new technologies will soon do the same for lithium.
You’re quite right. I was thinking of the “rare earth” metals.