What color of gem is best to use in an amplifier?
Same color as the gem amplified, that's for sure, but is pure better than triple color? Maybe double?
Depends on what effect do you like. Pure green has more poison damage than double or triple color gems, but they have aditional efects. The gameplay is not very different if you use 1 green 1 yellow or 2 green/yellow gems (this is not 100% true if they are at very different spots)