First Chair's Trumpet

Taken all the way down to base materials, one First Chair's Trumpet is 2 crafting steps deep and needs 3 intermediates — Deepgold Ingot ×3, Dwarven Mythril Ingot ×2 and Lignum Vitae Lumber ×1 — which resolve to 5 distinct raw materials totalling 29 units, plus 53 crystals.

That bill outweighs 10,170 of the 13,602 recipes tracked here and 1,028 of the 1,441 Armorer ones, and 4,464 recipes nest deeper.

Only 14 of those crystals go into the final step; the other 39 are burned by the intermediates, so the real crystal cost is 32 Fire Crystal, 7 Earth Crystal, 7 Ice Crystal and 1 other kind.

The chain crosses three disciplines — Armorer to Lv 80, Blacksmith to Lv 78 and Carpenter to Lv 78 — so no single class can finish it unaided.

All 5 raw materials are gathered, and not one of their spots is timed, so nothing in the tree waits on the Eorzean clock.

Of the intermediates, Dwarven Mythril Ingot has the widest use: 168 recipes call for it, spanning seven of the eight crafting classes.