I'm not so sure the sub-millimeter details are so mysterious if a sub-millimeter mark in hard stone is easy to feel with the fingers.
And if that's how they did it, this is still remarkable work.
And if that's how they did it, this is still remarkable work.
It’s possible to “shrink” a stamp by pressing onto wet clay, firing, and then repeating the process multiple times (clay will reduce after firing).
I wonder if this could have been etched or pressed, potentially with a chemical process?