Gabriel Soares said: can anyone tell me what's 'dual gem mastery' and 'ure gem mastery'?
Dual Gem mastery keeps the gem from getting weaker when you combine two different types of gems, For example, if you combine a green gem and a blue gem, then they won't lose as much range and added damage when combined. If you look at the description of the gem, it should say things like "range +20%" along with other stuff.
Pure gem mastery adds onto the perks that you already get when using pure gems. If you don't know what a pure gem is, it is just one single color of gem that is not combined with other colors. So for example, if you have a pure gem, and you are looking at the gem description it will say something like "damage +19%" but that is when you have pure gem mastery as opposed to "damage +10@$" but that is without pure gem mastery.