Silver .6g. largest diameter = 10mm
This was an experiment using a dissecting scope (stereo-microscope) to shoot a very small coin and restore missing depth of field with Helicon Focus. While it worked, there was no gain over the same thing shot with a lens that could be stopped down conventionally.
Dents on the center of the head and owl might be teeth marks. Small coins of this period (before the invention of pockets)were often carried in the mouth.