system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does carbon dating differentiate between the age of a material and the time that the material was shaped?

I see carbon dating used all the time to give the age of stone tools.  I always think to myself that the stone itself could be millions of years old, yet the carbon dating will put the age of the stone tool at tens of thousands of years old.  How does carbon dating differentiate between the age of the stone and the time that humans shaped it into a tool?
gpt
Stone itself can't be carbon dated.  There are other types of radiodecay dating that may work, but as you're saying they tend to show a geologic age.

Rather than dating the stone axe head, archaeologists will date the surrounding material.  The axe was thrown in a garbage pile or buried with someone, and that provides the carbon-based materials for dating.