印璽[inji] imperial seal
玉璽[gyokuji] sovereign's seal
剣璽[kenji] sacred sword and jewels
御璽[gyoji] imperial seal
国璽[kokuji] the seal of state

璽書[jisho] document with the emperor's seal
御名御璽[gyomeigyoji] the imperial or privy seal
国璽書[kokujisho] (Britain's) Lord Privy Seal
神璽[shinji] Imperial regalia (esp. the jewel Yasakani no Magatama)