With my luck, my 3yr old would trip over it, then proceed to throw it in a river/lake/deep hole!!
I don't know how it works in AUS, but here in the UK we wouldn't "own" that hold and wouldnt be able to claim it. The wicked witch of the west (Elizabeth Windsor) would try and claim it....
I think your 3yr old would struggle to throw this rock, Lol. In Australia it's finders keepers when it comes to gold nuggets. In some states you are supposed to have a fossicking permit from the gruberment to go looking, cheers mate.