Speed chains continue into Gem Mode. Since making matches in Gem Mode is quite easy, receiving new special tiles while still in Gem Mode should be a regular occurrence. Sometimes this will be a Time Tile, another Gem Mode Tile (prolonging Gem Mode), or a Wild Tile. When you receive a Wild Tile, activate it while still in Gem Mode. This will clear the entire puzzle, so this is also a great way to get your Gemologist achievement. Combine the strategies from these two achievements to give you better odds at both of these achievements, as well as a fighting chance at High Five.