When you hear "philosopher's stone," the first thing that comes to mind might be Harry Potter trying to stop Lord Voldemort from using it to restore his power.
But the idea of a philosopher's stone has been around for thousands of years.
For ancient alchemists, it was their ultimate goal in life: to create some kind of object or process that could turn common metals into gold.
They mainly focused on lead, and the recipes they came up with were as numerous and bizarre as the alchemists themselves.
Some called for things like urine, bones, and cat hairs.
They never actually succeeded in their quest to achieve transmutation — the conversion of one element into another.
Or in creating an elixir that would make them immortal, which is the other thing they thought a philosopher's stone might be able to do.
These days, we still can't make ourselves immortal.
But with some serious equipment, we can change atoms into different elements.
We can even turn lead into gold.
