I just finished my first shattered rock statue in the museum on Sunday August 5th. Then on Wednesday August 8th (first time I had skilled since) I started receiving strange rocks again. The guide says that you must wait a week before rebuilding the statue again but I was already able to start putting the statue together again. I don't think there is any wait period between statues and if there is, it's less than the 1 week the guide states.