Cumberground

[silent-e at myrealbox.com]

>Cumberland, RI, is the home of Diamond Hill, the only source of
>cumberlandite in the world.  Cumberlandite is the "state rock" of RI.

I've just taken several geology courses, and now I'm fascinated. 
Could you tell us a little more about cumberlandite?
-- 
-- Eric  |  <silent-e at myrealbox.com>           <-- note new address

            "For surely we all die, like water spilled on the ground
             that shall not be gathered."            II Samuel 14:14