Rhonda,
How is your hammer coral doing? I am really sorry to hear about your problem. Would you please let us know what size the emeralds are, and if they did any damage.
I have heard in the past the larger emeralds will do some damage, but small ones are highly recommended for bubble algea, not only by those in these forums, but also on other sites. The advice you were given was not bad or incorrect. Unfortunately not all creatures act the same throughout the species.
We totally feel your fustrations, and many of have had our own problems. We can not guarantee the behavior of inverts, only give you general rules that apply. My oldest daughter has a cat the hisses at and totally dislikes most people, but this does not mean all cats are that way.
Once again, we are sorry for your problems, and the advice was not incorrect.