A little experiment I did with MATLAB (well, Octave, technically) today, involving generating metal ore resonances when a sound traverses them. I give myself an FFT of it, and let myself hear it—which is actually much more useful—and try to figure out what it was.

Obviously this is very, very, very early stages; but, I think it's something I could build up into a marketable product, really. You ear just gets it after a while. The noise needs some work, and sometimes we're dealing with multiple metals at once; but it's doable.