This image has been taken using a Carl Zeiss microscope with Ultra Long
Working Distance Objectives (40mm) in dark field.

The indent has been created using a Schimatzu micro hardness tester at high
temperature (1500 centigrade) so you see the indent burning like amber.

The approximate size of the indent (diagonal) is 95 microns. I was pretty pleased
that the Professional could capture the fine texture details even in Dark Field.