Talk:Gems/@comment-24297775-20140317222828/@comment-3991817-20140317230816

The problem is there are better buildings to use the Gems on every time you level up. Like I said a couple of comments down I put my Black Agate on a Bowling Club as that was the building with the highest repair costs for me at that moment. But at level 40 it will take a while before you come across a building that has higher repair costs than the Parachute club, so it would make a fine building to use the Black Agate on.

I just calculated it myself out of curiosity but the difference in profitability between the two options is reallllly low (0.45%). The only thing is that the Elven Emerald also increases the building's hourly xp income a little (to 0.16 on lvl5).