Seeing a Mountain in a Grain of Garnet

Abstract
The collision of continents, which results in mountain formation, takes place through subduction, in which one slab of crust is pushed below another. The rock that is subducted is put under high pressure and new mineral phases can form. As discussed in the Perspective by Liou et al. , a report by Darling et al. in the same issue ( p. 91 ) describes a low-pressure mineral--cristobalite--that was found in high-pressure rocks. Understanding how this low-pressure form of silicate was created and preserved may lead to better understanding of the process of subduction and how deep material is brought to the surface.