This is a very interesting discussion about the Stone of Destiny and it's history by Jacob's Ladder, JacobIsrael.com.  The Stone of Destiny is not an ordinary stone but has built in power. That is why coronations are performed while sitting on the Stone of Destiny.  The history goes back to the Bible and Jacob's Pillow which was of stone and was later called the Stone of Destiny.  He describes all the many stories that the stone has to do with. Mirrored