Only found this on Help Center.
As for your question, you can see it in tool tips on the game, in the back box on your right side when you read each spell. This is a small summary.
Gems interactions
- Explode gem- take out a gem, and 8 gems around it. (3×3 grid), then take 50% of their mana.
- Destroy gem - take gems out from the board, and gain full mana from them.
- Remove gem - take gems out from the board, but didn’t gain any mana from them.
Main damage dealing
- Damage all enemies/Full AoE - deal damage to all 4 enemies based on the magic and boost of your spell
- Scatter/split damage - divide all your damage, and deal them to all 4 enemies. The damage amount on each troop random, but it can take out troops if their life is less than 1/4 of your total spell power.
- Splash damage - deal damage to single enemies, and half of it to troop on both sides.
Other forms of dealing damage
- Mana Burn - one form of Full AoE damage, but also boosted by the amount of mana enemies have. Deal no damage to troop that immune to it. (Impervious/Mana Shield trait)
- Devour - remove a troop from enemies’ side, then take its life/armor/attack as your own. (No magic gain)
- Lethal Damage - remove a troop from enemies’ side, but take no stats from it. Other words that got meaning similar to “destroy” will also work like this one. (Destroy/Kill/Slay etc.)