Squashed South Canyon Thunderegg
This one has been curiously squashed during formation, with the bottom edge punched in by some kind of external pressure. This was then 'frozen' by the agate formation.
9cm
Countries:
USA - Canada - Alaska - Mexico - Argentina - Peru - France - Germany - UK - Poland - Greece - Turkey - Romania - Bulgaria - Slovakia - Kazakhstan - Uzbekistan - Russia - Japan - Ethiopia - Iran - Australia - Unknown