So... I got much more brave with my fantasy and made a pendant as if I was making it for myself. That means I have not been afraid of adding as many sea creatures and details as I wished.
There were two specific conditions, though. There needed to be a seahorse covering a white spot in the stone... and a turtle, of course :)
Beautiful colour this chrisocolla stone has! I have a rock similar to this one. I cannot wait now to make my own pendant with it!
Update: she liked her pendant very much!