Reference article
Golden Gem (Duck Life 9: The Flock)
This can power up the tournament lift in Cloud Kingdom
Obtaining
Complete all four gem events in 
Cloud Kingdom: collect the first gem, find the storm-cloud gem, beat 
The Cloud Princess and defeat 
River, 
Boulder and 
Glyde. The fourth event reward is the Golden Gem.
Using it
Use it to power the tournament lift. You must also complete 
Cloud Pipes to obtain the 
Cloud Kingdom Tournament Ticket.