Public domain photos

The image shows a white surface with a ruler and a piece of paper with numbers on it next to it. On the paper, there is a scale with different colors and text written on it, as well as a stone with a number on it.

The image shows a white surface with a ruler and a piece of paper with numbers on it next to it. On the paper, there is a scale with different colors and text written on it, as well as a stone with a number on it.Open in library