Lode Ore
Lode Ore can be mined with any pickaxe to make Lode Cobble.
Mining Strategy
Lode Ore can be found surrounded by Stone at any height in the world. A darker "hint" texture indicates the presence of lode nearby, but not necessarily adjacent.
High in the world, lode can be found very frequently in small clusters. Find an exposed wall with lots of the lode hint texture on it, and dig small tunnels 3-4 nodes apart, to search for these small pockets of ore.
Deeper in the world, lode appears less frequently, but in larger clusters. You may be able to find these while lighting up caves.