Iron Scutum

Taken all the way down to base materials, one Iron Scutum is 3 crafting steps deep and needs 3 intermediates — Iron Rivets ×3, Iron Plate ×2 and Iron Ingot ×7 — which resolve to 1 distinct raw material totalling 21 units, plus 16 crystals.

That bill outweighs 8,152 of the 13,602 recipes tracked here and 780 of the 1,441 Armorer ones, and 337 recipes nest deeper.

Only 4 of those crystals go into the final step; the other 12 are burned by the intermediates, so the real crystal cost is 10 Fire Shard, 4 Ice Shard and 2 Earth Shard.

The chain crosses two disciplines — Armorer to Lv 24 and Blacksmith to Lv 18 — so no single class can finish it unaided.

Its single raw material is gathered, and no spot for it is timed, so nothing in the tree waits on the Eorzean clock.

Iron Scutum is itself consumed by 1 further recipe, all of them Armorer recipes.