[Rockhounds] Coating on rocks near Globe, AZ

[R. Peter Richards]

The obvious guess would be malachite, but there are several other  
copper secondary minerals that would be possibilities.  Given your  
observations, it would be an interesting experiment to turn over some  
of the rocks, and see whether the green that is exposed goes away and  
whether the previously exposed part becomes green.  And how long it  
takes....

Pete Richards


On Nov 25, 2008, at 12:22 PM, Al Balmer wrote:

> On the west side of Globe, there's an area on the edge of a mine dump
> which has common stone covered with some green copper mineral. This is
> evidently a short-term process, since rocks half-buried in the dirt
> have the coating only on the covered part.
>
> I'm curious as to what the coating is, and what the mechanism is.
> Anyone know?
>
> -- 
> Al Balmer
> Sun City, AZ
>
> -- 
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___________________________________
R. Peter Richards
rpr at heidelberg.edu
Morphological crystallographer





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