In the mountains last week I picked up a cool-looking garnet schist. But curses, the garnets had been resorbed! I was victim once again to retrograde metamorphism. Now I'll have to wait until I've acquired that coveted thin-section machine and petrographic microscope before I can study what happened. It's rather common for rocks coming down from high pressures and temperatures to revert to minerals that are stable at less extreme conditions. At least I got a new thing to put into the Geologic Features and Processes Gallery.
Ex-garnet schist Geology Guide photo