Couple of sites for people to peruse. Might find some answers to questions if you explore them. Not definitive.
http://www.goldprice.com.au/
http://www.ainsliebullion.com.au/easyweb3/IDf9b48dc8771011/?MIval=ew_view&WEBID=78594&ep_code=e004p01_stdEshop&page_code=buying_selling
http://www.kitco.com/
http://www.goldseek.com/