Cobalt Rivets

Taken all the way down to base materials, one Cobalt Rivets is 2 crafting steps deep and needs 1 intermediate — Cobalt Ingot ×1 — which resolves to 2 distinct raw materials totalling 3 units, plus 10 crystals.

That bill outweighs 3,373 of the 13,602 recipes tracked here and 410 of the 1,932 Blacksmith ones, and 4,464 recipes nest deeper.

Only 5 of those crystals go into the final step; the other 5 are burned by the intermediates, so the real crystal cost is 10 Fire Shard.

Every step is Blacksmith work, from a Lv 42 intermediate up to the Lv 43 finish, so one class covers the whole chain.

Both raw materials are gathered, and no spot for either is timed, so nothing in the tree waits on the Eorzean clock.

Cobalt Rivets is itself consumed by 50 further recipes, spanning six of the eight crafting classes.