1st core gives you specialization boost like combo dmg9% /crit dmg 9% or glancing effect 6.5% for tank. 2nd core gives you specialization attribute like combo, crit and glancing by 131 thats a huge boost. 3rd core give you a chance to increase your inscribed stone skill by 12.5% also additional HPS 2% for 5sec. With incribed stone skill active your skills will be enhanced for a while. Get at least at lvl 1 on all cores then focus on your specialization attribute.