Thanks for the comments everyone! The rock is a decorative lanscape lava type rock. It originally was a giant 200lb rick that I took a sledge hammer to to make smaller pieces. Based on info from the "reefers" on reefcentral, I took about four rocks and drilled a hole in them to make the column and then inserted a fiberglass rod with epoxy putty to hold the main structure together. Then I used many smaller ones to make "arms" and ledges. I used the epoxy and AC glue to hold them together. Actually it was easy! Since anubias and java fern do not grow well in the sustrate, I glued to seperate smaller rocks and just placed them, not glued them onto the structure. This way I can move them around or remove them easily if they shoud die.
thanks for looking
-mark