Need an idea on how to get gold

[megaflame566]

I am making a defense map like island defense and vampirism but on my map your in space in a ship and your ship has an alien in it i figured how to get lumber(Gold in the game) but i need an idea for gold that is hard to get but not to hard
I was thinking to make gold into alien samples but i wouldn't know how they would get it any one have any ideas it does not have to be my idea

 

[8uY_YoU]

What about using treasure chest and can be opened when the alien return to his base