Skybuilders' Stone

Taken all the way down to base materials, one Skybuilders' Stone is 2 crafting steps deep and needs 1 intermediate — Slate Whetstone ×1 — which resolves to 4 distinct raw materials totalling 21 units, plus 9 crystals.

That bill outweighs 8,152 of the 13,602 recipes tracked here and 1,199 of the 2,216 Goldsmith ones, and 4,464 recipes nest deeper.

Only 6 of those crystals go into the final step; the other 3 are burned by the intermediates, so the real crystal cost is 7 Wind Crystal and 2 Fire Crystal.

Every step is Goldsmith work, from a Lv 61 intermediate up to the Lv 70 finish, so one class covers the whole chain.

All 4 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, Slate Whetstone has the widest use: 33 recipes call for it, spanning two of the eight crafting classes.