YMMV / Steven Universe S5E22 "Made of Honor"

• Genius Bonus: Bismuth tells Steven "I'm not as dense as you might think", which in context can be taken that she is far smarter and wiser than people realize. However, the actual element Bismuth is a post transition metal and her statement describes it perfectly. The mineral bismuth was considered stable for many years and was only recently discovered to be very slightly radioactive (with a half-life so absurdly long^note as in billions of times older than the universe! that it might as well still be considered completely safe), fitting the solid statement. It is noted as being the most diamagnetic natural element and has a wide variety of uses both as an element and as a compound, alluding to flexible and diamagnetic. Finally, its density despite being heavier atomically than lead and gold is only half that of gold (9 g/dm3). What is a nice little boast by the character is also a huge one for the writers who clearly knew what they were saying. Finally, Bismuth being a blacksmith (metalworker) is on point as she is literally a metal that makes iridescent crystals.
  "I'm made of the most solid, flexible, diamagnetic stuff there is and I'm not as dense as you might think."

---