Hello Mmowned,
(First of all, sorry for the game in French :P)
I just found an awesome Elementium and Pyrite nodes farming place in Twilight Highlands :
As you can see, there are plenty of nodes (up to 6-7) in a small part of Twilight Highlands.
Here is the place :
Important : Nodes only appear if you haven't finished all the quest in Twilight Highlands. I made 53/95 and it still works, so be carefull if you want to use it for a long time I stoped questing at Dressed to Kill
You'll usualy find 5 or 6 Elementium nodes and 1 Pyrite node
After mining, you'll just have to wait 5-10 minutes and other nodes will appear
This works on (FR) Temple Noir, don't know about the other realms...
EDIT : Just made 50*Elementium Ore and 10*Pyrite Ore in 20 minutes