An Aztec turquoise-mosaic mask, c. A.D.
1400-1521, in the British Museum.
I'm lost then found, dug up from the ground- something to save or hide away in a cave. I can re- write history or open up a new mystery. My value is set in your own clear mind. It all depends on what you find.
What am I?
Answer: Archeological/ buried treasure