The mint has been issuing coins made of gold which are money, and not commemoratives? What are the dollar amounts now in circulation, and what images are on them?
Commemoratives are legal tender.
Only a few have ever been released at face value however.
(Unsold Isabella quarters were dumped into circulation in 1893 for example.
The State Quarters are circulating commemoratives.)
And many early commemoratives were put in circulation during the Depression when their owners were short of cash.
If the price of gold and silver ever fell below face value, you would see them circulate.
Go see what they make at the US mint webpage. These are investment coins, although they are easy to turn back into cash. Congress authorized the sale of $50 gold bullion American Eagle coins back in 1986. They list from $885 down to $85. They also have plantinum and silver American Eagles.
The $50 American Buffalo 24 K gold coins authorized in 2005 are really nice for $800. There is also a SF mint $5 gold coin for $255