rare earth oxides
By Energy and Minerals Mission Area
June 2005 (approx.)
![](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/thumbnails/image/d115-1.jpg?itok=v2CqCVt2)
Detailed Description
These rare-earth oxides are used as tracers to determine which parts of a watershed are eroding. Clockwise from top center: praseodymium, cerium, lanthanum, neodymium, samarium, and gadolinium. Image Number D1115-1. Photo by Peggy Greb, USDA-ARS.