Solid-brick Interior Wall ★★

Taken all the way down to base materials, one Solid-brick Interior Wall is 3 crafting steps deep and needs 5 intermediates — Clinker Bricks ×5, Firebricks ×5, Mortar ×4 and 2 others — which resolve to 8 distinct raw materials totalling 56 units, plus 56 crystals.

That bill outweighs 12,997 of the 13,602 recipes tracked here and 1,546 of the 1,591 Alchemist ones, and 337 recipes nest deeper.

Only 14 of those crystals go into the final step; the other 42 are burned by the intermediates, so the real crystal cost is 38 Water Shard, 7 Lightning Crystal, 7 Water Crystal and 2 other kinds.

Every step is Alchemist work, from a Lv 1 intermediate up to the Lv 60 finish, so one class covers the whole chain.

All 8 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, Mortar has the widest use: 140 recipes call for it, spanning six of the eight crafting classes.