Steel Mortar

Taken all the way down to base materials, one Steel Mortar is 2 crafting steps deep and needs 2 intermediates — Steel Ingot ×2 and Walnut Lumber ×1 — which resolve to 3 distinct raw materials totalling 9 units, plus 12 crystals.

That bill outweighs 5,492 of the 13,602 recipes tracked here and 597 of the 1,932 Blacksmith ones, and 4,464 recipes nest deeper.

Only 6 of those crystals go into the final step; the other 6 are burned by the intermediates, so the real crystal cost is 7 Fire Shard, 3 Earth Shard and 2 Wind Shard.

The chain crosses two disciplines — Blacksmith to Lv 32 and Carpenter to Lv 25 — so no single class can finish it unaided.

All 3 raw materials are gathered, and not one of their spots is timed, so nothing in the tree waits on the Eorzean clock.

Steel Mortar is itself consumed by 1 further recipe, all of them Blacksmith recipes.