Darksteel Ingot ★★

Taken all the way down to base materials, one Darksteel Ingot is 2 crafting steps deep and needs 1 intermediate — Darksteel Nugget ×2 — which resolves to 2 distinct raw materials totalling 15 units, plus 7 crystals.

That bill outweighs 6,735 of the 13,602 recipes tracked here and 730 of the 1,932 Blacksmith ones, and 4,464 recipes nest deeper.

Only 1 of those crystals go into the final step; the other 6 are burned by the intermediates, so the real crystal cost is 6 Fire Crystal and 1 Fire Cluster.

Every step is Blacksmith work, from a Lv 50 intermediate up to the Lv 50 finish, so one class covers the whole chain.

1 of the 2 raw materials come out of the ground, and one of them is time-gated: Darksteel Ore (1:00). That window comes round once per Eorzean day, every 70 real-world minutes.

Darksteel Ingot is itself consumed by 42 further recipes, spanning six of the eight crafting classes.