Deepgold Arquebus

Taken all the way down to base materials, one Deepgold Arquebus is 2 crafting steps deep and needs 4 intermediates — Deepgold Ingot ×2, Cobalt Ingot ×1, Crimson Firesand ×1 and 1 other — which resolve to 8 distinct raw materials totalling 25 units, plus 41 crystals.

That bill outweighs 9,313 of the 13,602 recipes tracked here and 1,056 of the 1,932 Blacksmith ones, and 4,464 recipes nest deeper.

Only 12 of those crystals go into the final step; the other 29 are burned by the intermediates, so the real crystal cost is 18 Fire Crystal, 6 Earth Crystal, 6 Water Crystal and 2 other kinds.

The chain crosses three disciplines — Blacksmith to Lv 73, Goldsmith to Lv 72 and Alchemist to Lv 71 — so no single class can finish it unaided.

All 8 raw materials are gathered, and one of them is time-gated: Gold Ore (9:00). That window comes round once per Eorzean day, every 70 real-world minutes.

Of the intermediates, Cobalt Ingot has the widest use: 145 recipes call for it, spanning seven of the eight crafting classes.