The stone was the Stone of Scone, where the CELTIC kings were crowned with an archaic ritual since time immemorial. This tradition was lost through various tribal wars until Robert BRUCE reintroduced it, crowned King of Scotland there. The stone was later "stolen" by the English king. Where the Judaic claim to the Scottish throne is supposed to be here does not open up to me.
Btw. there is no Stone of destiny but the Spear of destiny or the Holy Lance.