Originally Posted by
hallucin8
As someone who has played for the last decade, I have no idea :p Hehe. But at a guess, you want to be looking for mobs in the level rage of 11-20, specifically of the Aegis variety. In the upper echelons, T6 crystals drop from Maggots (Doom) and Fyakkis (Eastern Deadlands). You are very correct that Undead will not drop crystals of anykind. As a starting point, I think there might be some maggots in/near the Isle of Drowned (sp?), the island to the south-west of Parsinia.
Good luck, happy huntings :)