Hi Steve,
SF>yeah me too 1 have used about 50 ib of live rock apparently from the 
carrabe
SF>but how can i check?
Depends on the kind of rock. Talk to someone who knows about geology,
otherwise a marine biologist. A student of molecular biology will
probably know enough to offer a good opinion. Failing that, analysis of
the chemical composition of the surface would give a very accurate guide
to its origin. From a virgin (dry since removal from source) sample, a
salinity test would be pretty conclusive too.
Personally, I don't use live anything. When I bought a chunk of cork
bark for my bullfrogs to sit on, It stayed in the microwave until it
started to smoke!
Dave
--- ViaMAIL!/WC4 v1.30 
---------------