Collect 8 Pyre Tongue Shards in Wurmscale Barrens ( 159, 135, 738 ) Copy/waypoint 159, 135, 738 . Red crystals at edges of pools of magma. They are very abundant; you should have no trouble finding them.
Note: They are not trackable and may be difficult to see unless you zoom in.
Once again, Level of Detail Bias to the rescue! Turning this up can make a LOT of difficult-to-see harvestables viewable from much further away. And it has very little effect on FPS or lag. (Options - Display - Model Detail, the first slider.)