Wow.

2-gem fusions: 36 total

3-gem fusions: estimated to be 84 total

4-gem fusions: NOT GONNA CALCULATE

5-gem fusions: NOT DOING IT

6-gem fusions: NOT DOING IT

7, 8, 9, 10, 11-gem fusions: NOT DOING IT

12-gem fusion: A giant blob of Earth-destroying mass.