a crystalline rock that can be cut and polished for jewelry; "he had the gem set in a ring for his wife"; "she had jewels made of all the rarest stones"
concerned with or characterized by rigorous or adherence to recognized forms (especially in religion or art); "highly formalized plays like `Waiting for Godot'"
being or characterized by concepts or their formation; "conceptual discussions"; "the schizophrenic loses ability to abstract or do conceptual thinking"; "sex is a notional category, gender is a grammatical category"