2015 Silver Koala 1 Oz High Relief Product VideoOften the word piedfort is translated as double-thick, but this is neither a literal translation nor a precisely accurate definition. Australia 2015 high relief piedfort 3 coin silver proof set kangaroo koala kooka denomination 3 x $1 one dollar. These coin are struck in ultra high relief, with a frosted cameo proof finish each is a piedfort.