Mystery: Formation of Mineral Deposits in Earth and Big Bang
From the essay
I was always mystified: how come that at some places in earth we have gold deposits, in others – iron, in others – cupper, in others, even more mysteriously, diamonds which is not a chemical element! How the tiny atoms of gold find other tiny atoms of gold? Or atoms of iron find iron… We have seven main theories of formation of such deposits. In my mind, there is something wrong if to explain a single phenomenon, admittedly fairly complex, you need not one or two but SEVEN different theories!
Adapted from PDF pages 1.