The Piece of Stone is one of the missing items that you need to recover and return to the correct time period. This Sun Stone Piece must be return in the time of Aztec Empire(1519 AD – 5’oclock in your Time Device) give it to man with headdress.
How to Get the Piece of Stone
The Sun Stone Piece is in one of the chimneys at Thomas Edison’s house (9 o’clock, 1877 AD in your time device). Go left to the horseless carriage and start it, and ride it to the tree, to reach the roof. The stone is in the second chimney.