Rarefied Book of Aurum Regis

Taken all the way down to base materials, one Rarefied Book of Aurum Regis is 3 crafting steps deep and needs 4 intermediates — Aurum Regis Nugget ×2, Enchanted Aurum Regis Ink ×1, Hardsilver Ingot ×1 and 1 other — which resolve to 7 distinct raw materials totalling 29 units, plus 35 crystals.

That bill outweighs 10,170 of the 13,602 recipes tracked here and 1,354 of the 1,591 Alchemist ones, and 337 recipes nest deeper.

Only 11 of those crystals go into the final step; the other 24 are burned by the intermediates, so the real crystal cost is 19 Wind Crystal, 11 Water Crystal and 5 Lightning Crystal.

The chain crosses two disciplines — Alchemist to Lv 60 and Goldsmith to Lv 58 — so no single class can finish it unaided.

6 of the 7 raw materials come out of the ground, 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, Aurum Regis Nugget has the widest use: 185 recipes call for it, spanning seven of the eight crafting classes.