How to collect gems?

The path of a free-to-play player is tough, but the sense of accomplishment is that much greater. Don't forget to complete your daily quests and achievements every day, and don't miss out on events. Applause for your elegant patience. Your elegance score: 96 points!!

I always did the boss fights and the twice-daily mine runs because they give a lot.

Gotta watch the ad.

When you get gems from boss or mine challenges, watching ads gives you 4x I think. I know it gives from 120 at least to 450 at most. You can enjoy the game enough without spending real money.

Beating the boss and the mine, then watching ads for rewards is the way to go ㅠㅠ Keep it up!