there are now 2 different items with the name lu coin. the first one was from the original special quests way back when.

1. The Lu Coin generates 5000 gold pieces every 5 minutes! Item Details:Stock Left: UnlimitedPremium Item: NoItem Boosts:+5000 Gold/5 Min

the new one seems a lot better, with a similar but different image

2. The Fu Coin is an incredibly powerful legendary item. Not only does it provide 2% luck increase for each owned, but it also offers an incredible +15000 equip defense each! Perfect for those that want to win battles with others players as well as increase drop rates from quests and bosses.
Item Details:Cost: 25000 credits
Stock Left: UnlimitedPremium Item: NoItem Boosts:+15000 Equip Defense

maybe as the description says it was meant as the fu coin?