https://webshop.cashconverters.com.au/item/2796950/coin-100-dollar-australian-kangaroo Not that anybody should buy at this outrageous price even if it was genuine, but just goes to show buyer beware when buying second-hand with regards to authenticity from a non-bullion/coin dealer who may not have much experience or appropriate testing equipment.
Mate of mine used to own a Cash Converters. Reminds me of a story he once told about having to go to court about some items that were allegedly stolen. Magistrate asks, "what is the value of the items?" Mate responds, "with respect Your Hounour...are you buying, or are you selling"
Na definitely fake. The obverse has an almost mirror-like surface when in reality a genuine gold kangaroo always has a "matte" background on the obverse. Plus the queen's portrait is just... off.