in recent years gold has generally trended upwards in price and so gold coins have increased in price too. Unlike silver, many minted coins (eg sovereigns, francs, guilders and more) which would have collection value in another metal are instead valued for their gold content and are often called "bullion grade" coins. I have been very lucky in collecting 'bullion grade' sovereigns here and received such high quality coins that they could be graded XF or Unc (about uncirculated) which makes their sellability higher and often gets me better price. See this link for coin grades: (
https://en.wikipedia.org/wiki/Coin_grading ).
There are bullion sellers that deal in these coins in Australia and give you a place to start. Note that even though the coins are priced for their gold value the premium (amount charged by dealer over spot) can be a bit higher than generic gold products. The trick is to learn which coins are sold as numismatic coins and which are being sold as bullion coins. For example Jaggards, Gold Stackers, Ainslie and others sell sovereigns. Bullion grade or common sovs go for around $450 at the moment. eg
https://www.ainsliebullion.com.au/p...3b23-1b72-4a79-a52e-a39b713cdae5/default.aspx
A standard sovereign contains about $386 worth of gold at time of posting.
https://en.numista.com/catalogue/pieces11463.html . This means that you are looking at least 15% premium on sovs as a minimum. Considering that GST takes up 10% from some sellers that is a pretty fine margin. Note that as a private person when you sell you don't charge GST which gives you an immediate (though small) advantage over bullion sellers' pricing if gold price has risen since you purchase.
Collectable sovs can sell for many thousands. I have enjoyed collecting sovs that sell for under $600 which allow me to get a range of coins from Melbourne, Perth and Sydney etc and designs including Shield, St George and Sydney Mint sovereign designs in the past. When I went through a tough financial period I sold off my collection sadly, and got good prices for them, which was pleasant.
So the message here is that while you can make more money on gold minted coins, you do need to do some research and take care in how you buy. It can be very rewarding so I do recommend it.