From http://www.oxforddictionaries.com/us/words/historic-or-historical:

"Historic and historical are used in slightly different ways. Historic means ‘famous or important in history’, as in a historic occasion, whereas historical means ‘concerning history or historical events’, as in historical evidence; thus a historic event is one that was very important, whereas a historical event is something that happened in the past."

I don't think that mysterical is a word, and I don't think you are going to see rustical, poetical or romantical very often.