Michigan Copper Minerals
In addition to copper the “poor rock” from the mines in the Keweenaw contains a number of other minerals.
Below is a list of some of the more common ones.
White - Calcite or Quartz
Blue – Chrysocolla
Light Green - Prehnite
Grass Green - Epidote
Dark Green – Chlorite, Chlorastrolite
Pink – Prehnite (with copper)
Orange – Laumontite
Red – Microcline(feldspar)
Copper – Copper :-)
Silver – Silver ;-)
For more information.