I was tossing up whether to put this in the identification forums or here,i thought I'd have a better chance here seeing I know its Aussie.
I bought a lot of various tokens etc and included was this,It measures 20mm across and 25mm high,it weighs ten grams.Im unsure on the metal,most likely copper.I've looked online for it but cant find anything about it,I'm thinking its from some kind of proof set?

Any help appreciated,cheers in advance.
Ag.
edit:thickness is 2mm