Ok I just got this in action mode on level 10, although it should be possible as early as level 7 with a little luck and better planning. I realized that the best way to get enough of the board cleared to make 4 special gems at once would be to chain two lightning gems together. Any more would clear too much of the board. Even then you have to be very lucky. Build a couple of lightning gems and either get them close to each other or on the same line. Then build up to blazing speed and let them fly. Not sure if continuing to match helps or hinders but I was and it popped. Mostly likely the first or second special gem you create will be detonated to continue the chain and make room for the fourth. It does require quite a bit of luck. Also, as usual, play from the bottom when possible to increase the likelihood of cascades. Good luck.