Hey guys I went up to my local canyon road and picked up some rocks,cleaned them and found out they're sandstone with baked on mud or something white very soft like clay. May be clay. So I did some googling and found mixed reviews and mostly hobbyist saying its OK and sites saying it will kill your fish. This is my last stop before deciding to put them in with my cichlid's and community tank. I live in California so that common orange brown sandstone.