The Chosen Ones

Hello guys, i'm a newbie here, but i really love TCO campain, this is the best warcraft campaign ever, i've spent more than 18 hours playing, especially chapter 6 costs me more than 6 hours to complete all things (like epic quest, elite quest). However, in chapter 6 my digging still 9/10, and i can't find "decimantion", i've readed the entire helping area to solve it, however that still leave me no go. Some said that "Dig far North-east corner outside Kar'gath", and i tried and found an "elixir" OMG. And more, in chapter 5, i can't find "Amulet of Magic" from the Kaza shop, can't done the diamond set though. Please give me an answer. Lastly, thank Aeroblyctos for this awesome campaign.