There's a famous oopart called the London[, texas] hammer which is a hammer of 19th century vintage which was found fossilized and embedded in a rock in Texas. I can't remember what the explanation is but somehow it actually underwent fossilization over the course of a few decades and came out looking like it was tens of thousands of years old.
https://youtu.be/Q-0ONrHP_2w?si=NHuCQIE72PJndqR4