'Diadem' in the Bible

Then another sign appeared in heaven: a huge red dragon that had seven heads and ten horns, and on its heads were seven diadem crowns.

Then I saw a beast coming up out of the sea. It had ten horns and seven heads, and on its horns were ten diadem crowns, and on its heads a blasphemous name.

His eyes are like a fiery flame and there are many diadem crowns on his head. He has a name written that no one knows except himself.