This Elementium Ore farming guide will show you the best places for mining Elementium Ore.
I must also mention that Pyrite Deposits are rare spawns of Elementium Deposits in Uldum and Twilight Highlands.
Twilight Highlands the best zone for farming Elementium Ore.
Uldum is a great alternative if someone is already farming at Twilight Highlands.
IMPORTANT! If you are level 50+, you will see the patch 8.3 version of Uldum. You can talk to Zidormi to switch between the new and old low-level phase of Uldum. (if you open the map, she will be marked with a white text bubble at Ramkahen)