Okay, when you get your dragons past level 10 you will see they all form a little ball over their heads, so when you reach level 11, you will see this as way of acknowledging all your hard work thus far. Those balls will remain there until your dragons reach level 20. At that stage, your dragons will wear little spinning gold crowns over their heads. If you swing by Marc's place, you will see a few. Those crowns represent the highest achievement of all - level 20 dragons.
The shrines turn from bronze to silver when you reach level 10. That is quite an achievement as you will have leveled up 50 dragons that contains those elements...that's why hybrids are the best, because they level up multiple shrines depending on the elements contained in the dragon. Before metal came into play, a panlong dragon and a bloom dragon covered all 7 elements. As people began to get strategic and worked on these two dragons, bloom disappeared from the market.
Once you get 50 dragons to level 15, (of the same element) all those beautiful shrines that adorn your islands will turn gold. That's when the shrine grind really begins...so, happy breeding family, because the bigger they get, the more hungry they become.