A Fallen Virtue
I see no need for this. Gold is terribly easy to make, and 25g is perfect for what it is: a tip.
You wouldn't give your waiter 500 dollars extra just because he gave you good service, would you?
lol one of my aunts and uncles actually did that once when they were in Thailand
xd Their dinner bill was already large enough, yet they gave their waiter a tip that was bigger than their dinner bill. According to my uncle, the waiter's eyes grew big as saucers when he saw the tip.
back on topic, I think 25g for tipping is already fine as it is.