Does anybody know if this can be done? I don’t know if they stamp passports at the borders but I really need to leave the Schengen zone on my Australian passport and then re-enter with my European one.

namloc,
well you can leave the schengen zone with your australian passport flying to either morocco, uk or ireland.
when you land, go thru moroccan, british or irish immigration using your european passport.
fly back to the schengen zone using your european passport.
none eu passports are stamped upon arrival in and departure from schengen zone.

Thanks, but I was just checking if this can be done in either Andorra or Gibraltar?