Philosopher's Stone

Immortality in mineral form. Flamel, they say, is not actually buried in his tomb.

The alchemists' goal: a substance that transmutes base metal into gold and grants the elixir of life. Documented pursuit spans a millennium — from Jabir ibn Hayyan's sulfur-mercury theory to Nicolas Flamel's legend (the historical Flamel was a Paris scribe; the alchemist story was attached to him 200 years after his death) to Newton's laboratory notebooks. The conspiracy layer holds that someone succeeded and suppressed it. What is documented is the opposite: alchemy's failures produced real chemistry — phosphorus was discovered by an alchemist boiling urine for the Stone.