This ore type can be found only in the southeastern part of Shadowmoon Valley. You cannot mine this ore unless you have completed a part of the quest chain leading to the Netherdrake mount. To get far enough in that chain, you are required to have 150 riding skill, thats one costing 5000 gold to train. The ore itself is used purely for a reputation turn in, but the nodes do have a chance to net you eternium ore, gems and motes of fire or earth.