Magic Spins are our gift to you.
Spin gems can be won at both the Daily and Hourly bonus collection, this is however not guaranteed. 
When you have collected 7 gems you will be presented with a Magic Spin, where you can Win Free bonuses, as well as Free Spins and bonus rounds on any game - even if it is locked to you. 
You can increase your chances of winning spin gems though, by frequently collecting your hourly bonuses. 
The more bonuses you collect, the more likely you are to win spin gems.