Family of five natural coral rocks, Gathered from south Florida beaches. If you look close you can see where the coral has fossilized and is forming soft gold colored crystals. Best example is photo 4. Would be a fun project to put the smaller stones in a rock tumbler.
The larger coral rock is kind of twisted and gnarly. Maybe pressure wash it to bring out the crystals. Might be used to take a rope and pull it through one of the holes, tie an interesting knot and hang it up outside as a point of interest.