DescriptionRareearthoxides.jpg English: These rare-earth oxides are used as tracers to determine which parts of a watershed are eroding. Clockwise from...
jpg (di Michel Chevreul; PD) Trenntrichter.jpg (di Hannes Grobe; CC-BY-SA 4.0) Rareearthoxides.jpg (di Peggy Greb; PD) Commons-logo.svg (di User:Pumbaa...
