The blood-pumping organ of a greedy/
selfish moocher/fortune-hunter who only yearns for gold; i.e., his
main goal in life is to be given money to either hoard or spend frivolously.
In the 1937 comedy-film "Way Out West",
Laurel and Hardy play
a couple of witless buddies who unknowingly deliver a deed for a
gold mine to the wrong woman; the recipient is actually the heiress's devious guardian with a "heart of gold"... Laurel naively "hits home" by telling her, "Now that you own a mine, I bet you'll be a swell gold-digger".