live rock forming?

[richardhmc]

so im trying to redecorate my tank and im pulling all my live rock out and I pulled one out that was used as a base so it was embedded into the sand. when I pulled it out, the part that was in the sand was all gray and it looks like as if the bottom is all smooth and round! should I break this off? Its already pretty hard

 

[ming]

Probably grey from sulphur which form in the sand after a while. It might also smell like rotten eggs.

just FYI, Live Rock is formed from dead corals primarily

 

[richardhmc]

yeah right now it smells terrible! haha