Now the problem is, there are many things we can exchange... by giving up other choices. Here I have done some simple maths.
By the end of the event, one will amass a number of unrefined gems, approximately:
- 1200 from daily run, assuming you have a efficiency of using 20 hours worth of energy per day, 1440 gems if you are lifeless AF
- 210 from the event quest rewards
- 55 from the 11 extra hours on 1st December ( 5am~4pm GMT+8 )
- 125 by spending energy reward from the Curiosity quest rewards
So, give or take, you have 1600 unrefined gem to decide what to exchange by the end of the Curiosity event. Your choice, m8?
P.S: If you are able to do legendary mode without failing, maybe you will get 2500 unrefined gems by the end. But then again, what's your choice m8?
Edit: Considering you have really bad luck in gaining unrefined gems, it's still save to assume that you have 1500 unrefined gem by the end of the event, if you invest your time on it.