Public domain photos

The image shows a piece of rock sitting on top of a table next to a black board with numbers written on it. The rock appears to be a piece that has been cut in half, with the numbers clearly visible on the board.

The image shows a piece of rock sitting on top of a table next to a black board with numbers written on it. The rock appears to be a piece that has been cut in half, with the numbers clearly visible on the board.Open in library