if your stuck on level 78, maximize everything except the gem color mastery ones, save the mana gain and bouncing mastery ones, pure gem mastery, prismatic mastery, max mana, and readines. make a grade 4 gem with the gems u have, put it near the beginning, and keep making grade 5 dual gems out of grade 4 ones (it saves mana to start low and combine) and put them near the beginning. after that, make them grade 6 from grade 5, and so on. make sure that every gem is a dual gem, because of the max mastery u got, until the end when ur just gonna bomb them all. start with just 5 or 6 gems so when u need to make another type of gem, u don't waste any mana. remember to make the mana gaihn gems hit first so u get more mana. this level is not about making 7 grade 7 gems, it's about making 7 grade 7 gems as fast as possible. hope this helps, rate + if it does.