Here is an interesting recent find from the Trotter mine dump. It is a piece of concrete from an old mine building foundation and is probably a hundred years old. Fluorescent mine tailings were mixed with the concrete instead of the usual rock and sand. The red comes from calcite, the green is willemite, and the blue is hardystonite. This specimen was cut with a diamond blade rock saw to expose the fluorescent minerals inside the concrete.
 
 

Photographic Images © 2003 James O. Hamblen